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Chevy S10/GMC S15-Sonoma: Problems & Solutions



  • bone4bone4 Posts: 5
    YOu may no this but when you run you ac your using more gas! well it should lower your rpms whenyou do have the compressor on. so that may be why!!
  • mikeys10mikeys10 Posts: 7
    I think the most common answer from the dealer when they don't know why or what. They don't know. Today vehicles have onboard computer that will monitor everything. If your have a voltage fluxuation, it is not right. Check if other items are doing to same thing. if so possible alternator. If not could be bad harness connection at that components. The fact remains its not right. If its under wartity they must fix it.
  • mikeys10mikeys10 Posts: 7
    There is a device that can be plug into the computer prom. It cost about $135 at Autozone and must have some car smarts, it will monitor 5 or more functions. This small computer plug in and down load on your home computer and can determine what is wrong. but it sounds you might have a cloged fuel filter. does it buck some? Todays engines are computer control. They all have ECM's Engine Control Module.
  • mikeys10mikeys10 Posts: 7
    It sounds like you have a major fuel system problem. Your line should not be moving. Thats shotty workmenship, take it back , most fuel pump are in the tank which require to drop the tank. If your using bargan gas stop. start using top grade. thats your noise. Have the mechanic check fuel pressure to thottle body ejector. Your S10 has a ECM also the technician can hook up the prom to monitor the fuel system. Use different mechanics for specialize items. For tuff things the dealer shop is sometime best.
  • wowolfolwowolfol Posts: 2
    Right now, the owner of the company I work for is selling his 'old' 99 S-10 because he bought a new [luxury] car recently. The damn thing only has 27k miles (used to drive to and from work... about 8 miles each way) and the only mainenance needed has been a new alternator... although the driver's side recliner handle snapped off as many people here have had the same problem (how retarded). Anyway, he's willing to sell it for $5500 to me, being as how I'm his employee and I'm just that cool.

    Should I take the deal?
  • badass10badass10 Posts: 1
    start with the basic i guess, 99 2.2L 73k, no problems with the damn thing, till now, Something in the motor makes a noise i've never heard and i've worked on motors before, almost sounds like a bearing, it only happends when rpms are about 1k to 2.5k taking off or crusin at 40 and the tranny shifts down to that range. I've changed the belt tentioner 6 monts ago,alt 1 year ago and i need some help please, motor is running fine, sound is comming from from to left side of the engine, Guys if anyone could help that would be great..........thanks for your time............
  • bjynnisbjynnis Posts: 1
    1990 chevy s-10 pu has to idle at least a half an hour before drivabilty replaced fule filter, idle air control valuve, pulled gas tank, new sock, cleaned tank operated fule pump manualy pressure past thumb, all seems ok but brake fule lines after an hour of not running no pressure in lines.
  • Mike I have the same problems, very similar, i have a 2002 with 80,000(mostly highway). My gas gage does play around just like yours, it will read half full then 5 minutes later it could ready empty. The 4wd (4hi) is whats really worrying me tho. the same thing also is happening to me, it's not engaging all the time and it seems to be getting worse, meaning it's not engaging at all in 4 hi. I am planning on lifting my truck in 2 months and this is a big deal. If i find anything on the internet about how to solve this i will let you know, but i am going to tear open my transfer case either tomorrow or monday and have a good look at whats going on. i know alot of mechanics and i'm in the field of mechanical engineering. I will get to the bottom of this and let you know. In the mean time ( when u say transfer case control module) thats a computer chip or gears?
  • chances are , you need new window/door trim . i say this b/c of your phrase "air leak" i know your trim is pretty new, but sometimes things happen, such as winter or leaning against your window and taking it off it's support. find out where the leak is and if it's from the window then it's trim.
  • alcanalcan Posts: 2,550
    Check fuel pressure, check coolant temp sensor.
  • joe3891joe3891 Posts: 759
    There has been an issue with the timing chain tenioner on that engine coming apart. Check at the timing chain cover with a hose or wood rod to sound out the noise, if you can duplicate it without driving it.
  • somasoma Posts: 1
    Both you & the previous post should check your Catylitic Converters. I had this very odd rattle, that started off subtle, but got a little more obnoxious as the months went by. My truck still ran fine all throughout. Usually was more noticeable when running through the gears. Highway speed, idle & foot off the gas all made it go away for that time being too.

    To check, just roll under your cab, passenger side & locate the big oblong bulb-ish looking piece that is connected to your exhaust, usually just under where your passenger seat is located (but under the truck of course).

    Just kind of tap it with the palm of your hand (maybe a little harder than tapping, more like a solid trust) and see if that sounds familiar. More than likely the element inside has expired & would be rolling around loose in the metal housing. If you bang it & it's just solid, no rattling at all then it's probably something else.

    The crappy part is... if you live in California then you can only get an OBD2 compliant replacement which is about $456. No aftermarket alternative on that one. Though you will find them online for $56, $188 or $240 you must read the fine print because they're not OBD2 compliant & not valid in CA. OBD2's are ONLY available at the dealership.
  • "I am planning on lifting my truck in 2 months and this is a big deal."

    I have an S-10 Ls ext. cab vortec 4.3 4x4 and want to use it for offroading so i was considering lifting my truck as well. Also i want to get some protective skid plates on the bottem to protect the under chase from rocks and etc. Does anyone have experience with offroading with there S-10? if so did it preform well or was it a waste of time?
  • Kink #559 & Check #490....Looks like there's a few "suckers for a cute S10" out there. I've used my 4WD Hi a few times every week now and had no problems! Every time I went to the Chevy dealer they'd reset the TCCM by unplugging then plugging in the module under the passenger kick panel. Finally, I made them tell me how to reset it and threatened them if they didn't fix it they'd buy the truck back. They reluctantly replaced the encoder motor saying 'it couldn't be the problem, they never go partially bad'. GM called me back a few weeks later to say they didn't forget me, and gave me a 1 year smart care plan for oil changes at this dealer. I feel sooooo much better now. Does anybody need a free oil change? I can't wait to go back and tell them the gas gauge is still messed up. Give this message to your dealer when they say it couldn't be the actual actuator causing the problem.
  • wowolfolwowolfol Posts: 2
    So should I buy the truck or not?
  • londog77londog77 Posts: 5
    Now that I have spent way too much time and money replacing a fuel pump in the gas tank all weekend the problem is still there....but I have more information...hopefully somebody can help. There is a new fuel pump, fuel filter, and the fuel pressure is at 58 pounds which is perfect. So, I have narrowed it down to these symptoms. First the truck fires up just fine....then I can rev it up over and over again as if everything is 3 minutes when the truck is warming up and the idle drops to a normal warm running idle the problems still idles fine but when I rev it to 1800-2500 rpm the engine starts jumping and dropping off...hesitating and so starving for fuel or something. Engine shakes really bad when this happens. Could this be the pressure regulator or injectors..? I dont think it is electrical because it only happens when it warms up...I have also read something about having a bad ground but I don't think that is the case here....please somebody help...I am missing work now...which makes it worse. Any ideas.?
  • kc5gxckc5gxc Posts: 1
    My axle seal is leaking. I have the crew cab 2.2 5 speed. Anybody else have this problem? Do I have to pull the Diff. cover to remove the axle?
    Thanks, Pete
  • Ok i was told that chevy had 20,000 s10 that have a messed up wiring system. Well mine is one of them. The truck will not idle at anything less that 2800 rpms once the car is warmed up. The code for the throttle positioning censor comes up though it has been replaced a couple times. I have gone though the system and found no shorts but it doesn't mean that there isn't any because if i let the truck sit for a while the battery will be dead. pretty much every sensor has been replaced. If anyone has any ideas please help.
  • dblainedblaine Posts: 1
    I have a '88 chevy S-10 2.8. The fuel pump quit on me. I replaced the tank mounted pump but no luck. I got another pump and it ran great when jumped. After installation, it ran fine and the engine ran for about a minute. Now it's dead again. The manual said a bad oil pressure switch would make it inoperable. Replaced that and no luck. Anyone have a solution?
  • canufixitcanufixit Posts: 165

    Maybe this can help ???

    Fuel System - MIL ON/Rough Idle on Start-Up

    File In Section: 06 - Engine/Propulsion System

    Bulletin No.: 00-06-04-003B

    Date: February, 2003


    Rough Idle After Start, And/Or A Service Engine Soon (SES) Light
    (Unstick And Clean Central Sequential Fuel Injection (CSFI) Poppet
    Valves or Convert to MFI)

    1995-2002 Chevrolet and GMC S/T Models
    1996-2002 Chevrolet and GMC C/K, M/L, G, P Models
    1996-2001 Oldsmobile Bravada
    1999-2000 Cadillac Escalade
    with 4.3L, 5.0L or 5.7L Engine (VINS W, X, M, R - RPOs L35, LF6, L30, L31)
    Except 2002 VIN X - RPO LU3 Models

    This bulletin is being revised to update the Warranty Information. Please discard previous copies of Corporate Bulletin Number 00-06-04-003B with warranty chart (Section 06 - Engine). This copy is for Dealers in the state of CALIFORNIA ONLY.


    Some customers may comment on rough idle after start-up, especially if the vehicle has sat overnight. These symptoms may be intermittent. The Service Engine Soon (SES) light may also be illuminated. Current misfire or history misfire codes may be detected with the Tech 2 scan tool.


    A deposit build-up on the CSFI poppet valve ball and/or seat may cause the poppet ball to stick open or closed. In either case, the specific cylinder will be mis-fueled, resulting in a cylinder mis-fire condition.


    A new injector unsticking and cleaning process has proven to be effective in restoring poppet valves to an "as new" condition. CSFI injector replacement should NOT be considered as a correction for this customer concern.

    Check the vehicle history to determine if the vehicle is returning for a second fuel system repair for this condition. If the fuel system has been repaired for this condition previously, then inform the customer that an alternate fix is available. A new MFI fuel system has been developed that will back service the CSFI fuel system. The MFI fuel system eliminates the CSFI poppet valve ball and seat. The CSFI fuel system will need to be replaced as a unit. Refer to Central SFI to MFI Conversion instructions in this bulletin.

    Notice : Individual CSFI injectors can not be replaced with MFI injectors. The entire CSFI fuel meter body will need to be replaced. The bracket used to retain the injectors in the fuel meter body is different between the CSFI and MFI unit. The unit may not seal if you mix injectors. Severe engine damage could result.

    Cleaning the CSFI injectors is the preferred repair. The CSFI unit should not be replaced until cleaning has been attempted. If the vehicle should return for the same repair, then the CSFI unit can be replaced with an MFI unit. If the vehicle is out of warranty, the customer should be given the option of which fix to pursue.

    Important : "GM of Canada" dealers require District Service Manager approval prior to replacing the CSFI unit with a MFI unit under warranty.

    The first step of this process is to use the J 41413 Evap Pressure/Purge Station, in conjunction with the J 44466-10 pressure regulator/hose assembly, to provide the required high pressure (150 psi) source to perform the unsticking procedure. The J 39021 fuel injector tester and accessories provide the means to "energize" the injector. Some later model-year vehicles may utilize the Tech 2(R) to "energize" the injectors.

    The second step of this process is to run the engine on a solution of 10% Top Engine Cleaner and 90% gasoline. This will effectively clean any deposits from the ball and seats of the poppets. It is very important that the engine fuel system is separated from the vehicle fuel system. Top Engine Cleaner may have detrimental effects on the fuel pump.
  • 87vette87vette Posts: 1
    Canufixit, I'm new to the site and have a question re. 95 S10 2.2 2x2 I bought recently as a project. Plan to replace engine w/ mouse motor out of 2001 camero which received a 383 stroker but for now just playing with the 2.2. Pulled and replaced cyl head, cleaned injectors, new tps, new iac, new plugs,wires, fuel pressure regulator, etc. Now engine idles fast and has no power. Strong fuel smell at tail pipe. I'm thinking stuck exhaust valve on new head. Any ideas? Thanks. Bill Mc
  • canufixitcanufixit Posts: 165
    Ok, One more suggestion ...

    I have "heard" of the intake manifold to head gasket leaking in the front or rear ends of the manifold. This will allow coolant into front or rear cylinders ... If it is just leaking a little - you get a rough engine - if it's leaking a lot - it can fill up the pistons affected and cause a hydrostatic lock - and the engine will not turn .... Try a compression test on the cylinders ..... and look at the plugs when you pull them to see if they look wet (and smell them for the antifreeze ...).

    All I can think of right now ....

    Good Luck!
  • canufixitcanufixit Posts: 165
    In My case (on my truck) - the sweet spot is at 40 MPH. Just under /around/ just over 40 MPH on a light load on the drive train - the rear end whines. Take your foot off the gas - and it goes away. give it a little more gas and it gets louder - give it a lot of gas and it almost goes away. This is listed as "Normal" at 40 MPH in the shop manual for my Sonoma. It's not bad - so I just ignore it - but the root cause is incorrect pinion gear loading (shims) when the rear end finally broke in and the mechanicals finally seated ...
  • I recently purchased an 02 S-10 from a local Dealer (not chevy) and have discovered the carpet on the driver's side is soaked during rains. I can't find any source for the leak. Suspect cowling under wipers but don't know. Any thoughts suggestions? I can't find any information on the drainage sytem for the cowling fresh air intakes.
  • canufixitcanufixit Posts: 165
    See an Earlier Post I made on this - not sure if this is your problem though - Mine was the seam between the roof and the corner post not being sealed in the inside ...

    Good Luck!
  • canufixitcanufixit Posts: 165
    HI Bill,

    If memory serves me - a vacuum gauge will quickly show a stuck valve. Instead of a steady state at Idle the needle will "dip" drastically on every revolution of the engine ...

    I'd do a Cylinder pressure test (wet and dry) on each cylinder as well. With the pressure test and vacuum checks you'll have a better idea of the mechanicals and also a record for future reference ...

    A stong fuel smell at the exhaust may be Ok when the engine is still cold as more gas is poured into the engine until it get up to Temp. But as you said a "Strong" smell may not be right ...

    Good Luck!
  • canufixitcanufixit Posts: 165
    Can you jumper the fuel pump ?? - if you can get the pump running and the engines runs OK for a good while - at least you'd know that the pump is OK and its' the supply voltage/circuit to the pump that's the problem. This may help you in removing some of the variables in the equation. If it does not run - re-check the pump - it it runs - troubleshoot the wiring....
  • canufixitcanufixit Posts: 165

    I had an uner chassis rear rattle on intial engine start up - turned out to be a loose baffle plate inside the muffler.

    I'd get under the truck and really shake the exhaust - check both the muffler and the Converter (expecially the heat shield!!!)

    Good Luck!
  • dgh50dgh50 Posts: 3
    I was having the same problem with my 2002 S-10. I had a coolant leak at the thermostat housing and needed to drain the radiator but could not find an easy way to "turn" the plastic petcock. After maneuvering an inspection mirror into position, I could see an allen head fitting in the center of the petcock. I inserted a 3/8" allen wrench into the center of the petcock, and turned it counterclockwise approximately one quarter of a turn. It "popped" out slightly allowing coolant to flow from the radiator.
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