Chevy Silverado and GMC Sierra Gasoline Engine Problems

basspro

themajickman

Hello, first of all I'd like to say that I have scoured these forums for a solution to my problem and haven't found anything that could help. I am a quadriplegic and I don't drive but I am writing this to help my son who has a 1997 GMC Sierra 1500 with a 5.7 L vortec engine with 180,000 miles on it. The truck starts and runs fine until it warms up. After that, you can get the RPM up if you slowly work the accelerator but as soon step on it, the engine just bogs down until you back off the accelerator. It almost seems like it ran out of gas. He has replaced the fuel pump, fuel filter, the ignition module. It's not throwing any codes. Needless to say this is very frustrating and the truck is basically useless under these conditions. He isn't a mechanic and is unemployed at the moment so he just can't start throwing money at it. Any help that I can get here on this forum would be greatly appreciated. Thank you, Paul

themajickman

themajickman

bump...

wmaz

My 2000 Silverado has a P0300 code. I have done all of the stuff I have read about on the internet. New fuel filter, cleaned injectors, new plugs, checked for vacuum leaks, etc, etc. I finally gave up and took the truck to a mechanic. He found misfire history on cyl 1 & 6. Strangely they have the exact same misfire count. I took the #6 injector and swapped with #2. Drove the truck and went back. The same counts again on the same cylinders. Why 1 and 6? Why the same count? He now wants to check wiring since 1 and 6 fuel injector pins are next to each other on the PCM. There aren't any misfires at idle. Only at highway speed. I'm thinking the PCM is corrupt and should be flashed. Any other thoughts from you guys? Thanks

magiccat75

I have a similar problem. My 1999 GMC K1500 5.7L Suburban also bogs down when the accelerated is pressed. It will typically run fine for a while then it starts this. I find that it is easier to drive without the cruise control when this is happening because I can feather the accelerator to speedup slowly whereas the cruise control will try to accelerate more quickly which causes it to start missing/bucking then eventually the cruise will drop out. If I press the accelerator hard, it simply bogs down as 'themajickman' described. I have also found that turning the engine off then back on clears the problem for a few more miles. I have replaced the fuel filter and O2 sensors and I have also put a lot of fuel system cleaner through the system. The problem went away for several months but came back yesterday. I suspected the fuel system but turning it off for a few seconds should not be long enough to let the fuel pressure drop in case it is caused by trash. The engine light has only come on twice even this condition has existed for a long time, and the code did not give a good indication of the problem. The problem is not directly related to speed. One thing that may be unrelated is that if I put it in neutral and shut off the engine while driving (with a straight clear road, of course), it takes the speedometer 5 to 6 seconds to drop to zero. It continues to operate even though the key is off. Could this indicate a buildup of charge somewhere in the electrical system that could be causing the problem. Just a shot in the dark!

obyone

Sounds like a bad throttle position sensor

chuckieboy20

1999 chevy pickup 5.3 engine gettin codes of po171 and po 174 wonderin what they stand for

obyone

P0171 System too lean (Bank 1) O2 sensor detected a lean condition on bank 1 which is the same side as cylinder 1

P0174 System too lean (Bank 2) lean condition on side opposite bank 1

magiccat75

I replaced the throttle position sensor and at first it seemed like it might be better but on the road, the problem returned. Light came on so read the code again and it said the same thing as before, i.e. the O2 sensors, which I had already replaced. I then cleaned the mass air flow sensor with no improvement. I then replaced the MAF sensor and again, it seemed to run better at first but then the problem returned. To recoup the problem, it gets to where it will only accelerate very slowly. It won't even accelerate as much as the cruise wants to in order to maintain highway speeds on a slight hill. it stutters badly but when the accelerator is pressed hard, it does not stutter, but it also does not accelerate.

I ran another test. On the road, without being able to accelerate beyond just feathering the accelerator to accelerate very slowly, I floored it and the engine speed did not change significantly, didn't go up or down. Thought that maybe it didn't go down because of the transmission still being in gear so I shifted to neutral. The engine still held at the same RPM, even though it was in neutral (no load) and the accelerator was floored.

Here's what has been replaced.
- O2 (all four)
- TPS
- MAF
- Air filter

beveroll

We have 1994 chev 1500 truck was doing the same type of thing - would start to cough and sputter and seem as though it was going to quit running but never actually did. We would have to slow down considerably and found that if we shut it off and let sit for 5 or 10 minutes it would be fine for a while and then it would start again. We went through all sorts of things like map sensor, o2 sensor etc - someone suggested that the distributor is a problem on these vehicles, had it changed and the problem is solved at last.

snapoles

We were driving and all of a sudden we heard thisloud bang and all the alert lights went on. We pulled over & turned the engine off, but it would not restart and all of the gages went dead. We towed it home & it did not have any power and the window, which is electric, would no longer go up or down. What would have snapped to cause so many issues to occur at once?

beshaw57chevy

Hi I have a 99 GMC Sierra 1500 Z71 4x4 new body with a 5.3.I was told that 99 only will fit my truck,dose any one know if any other gmc year will fit?or chevy.
I really need the help,the dealer's here in Vermont are no help.
Thanks
George :sick:

obyone

What is it that you're trying to fit?

beshaw57chevy

I'm sorry it need a new motor and every one's saying 99 only will fit,

obyone

The manual shows that either a 1999 or a 2000 should work for your truck.

trevorwright

my brothers 91 siverado 2500 with a v8 and auto. trans. tachs out after warming up. the truck starts off slow and slowly picks up speed. it slowly shifts after the rpms have been high for a while. the tranny fluid is full.

trevorwright

hamberger

i have a chevy silverado 1500 5.3 and the waterpump went out. replace it and now when i drive a constant speed then let off the gas when i give it gas again it stutters realy bad. when the waterpump went out it did overheat. any advise?

tablerockjet

This truck, 07 gmc 2500 hd 6.0 litre gas.. has a throttle/run problem at cold start take offs, when I hit the gas, it just falls on it's face and I have to let completely off the throttle and just ease back into it untill it's rollin pretty good.. when operating temp comes up it's all ok. Anybody know about or had this same problem? Thanks for any help

tablerockjet

1998lincoln

This is getting to be a common problem with the 5.3L and 6.0L GM engines. went to Auto Zone to check my engine light, they said MAF sensor. replaced it, but no change. Auto Zone agreed to let return the MAF sensor (very nice folks down there) and was on my way to the dealer. Dealer ran diagnostics check, and found intake gasket to be leaking. ~$350 to replace on 5.3L. Don't waste your money trying a bunch of parts, go right to a Chevy dealer's service department to fix it right the first time.

1998lincoln

If chevy has a Mass Air Flow sensor, unplug the wires to it, then unplug the vaccum
hose and put your finger over the end of it,have someone start the engine, if it runs
smooth, replace the Mass Air Flow sensor !

Ford has the same problem !

1998lincoln

Two things, one, could be a collasped lifter, or rockers need adjusted !
If this does not help, replace lifters that are tapping ! Make sure it is not a
spark knock, caused by off timing or you are using low octane gas, when your
not suppose to !

1998lincoln

the low idle was a common problem on these engines. Actually, the real problem is that the accelerator is sticking (although this is not as evident as the low idle; this is why you feel the surge, instead of a smooth acceleration. The low idle is a by-product of this problem). The problem is due to hydrocarbon (sludge) buildup inside the throttle body, and possibly the air flow sensor. He cleaned both (I assume with something like common carb cleaner?).

1998lincoln

the low idle was a common problem on these engines. Actually, the real problem is that the accelerator is sticking (although this is not as evident as the low idle; this is why you feel the surge, instead of a smooth acceleration. The low idle is a by-product of this problem). The problem is due to hydrocarbon (sludge) buildup inside the throttle body, and possibly the air flow sensor. He cleaned both (I assume with something like common carb cleaner?).

1998lincoln

Check your manual, but You are right, I think 8' degress BTDC, not completly sure about that one. I do know the low idle was a common problem on these engines. Actually, the real problem is that the accelerator is sticking (although this is not as evident as the low idle; this is why you feel the surge, instead of a smooth acceleration. The low idle is a by-product of this problem). The problem is due to hydrocarbon (sludge) buildup inside the throttle body, and possibly the air flow sensor. He cleaned both (I assume with something like common carb cleaner?).

1998lincoln

Could be the engine temperature sensor! It was failing so it was telling the throttle positioning sensor that the motor was cold so it kept dumping allot if fuel. So when the gas was pushed it flooded it and it would die!

dentek

did you ever solve your problem i have the same problem

hollow3034

will fire sometimes. will run and then stop i have change the coil and it will run for a while and stop like something is getting hot i have change fuel pump, distributor cap n rotor ,spark plug n wires.coil n pick up coil n ignition control module still run n sptop

hollow3034

chuck_philbert

my truck was hit pretty hard. it has the 5.7 tbi, what other trucks can i put this in motor and transmission in?

buck4444

I am sorry if this has already been discussed here but I did not want to go through all the pages to see. I have a 99 and a 04 4x4 with the 5.3 v8. I am having the same problem with both. They are loosing water over time. I have been told it was the intake gasket. Does this sound right? The 99 is not as bad as the 04 and the 04 is smoking white smoke when first started. Is this related to the water problem? As you can tell I am no mechanic and I would appreciate any of your suggestions on this issue.

1998lincoln

You can tell if you have a blown head gasket, start the truck and watch the exhaust, if white smoke comes from the exhaust then you could have a blown head gasket ! Also, check the dip stick, look for drops of water on the stick !
Good Luck

buck4444

What about the 99? It does not smoke but it does loose water over time. I have to put water in it about every couple of weeks.

cliff85j

cliff85j

I have an 05 chevy silverado with 55000 miles on it. I have the oil changed regularly and dont abuse the truck. I put on 2000 miles since the last oil change. what would cause the truck to start using oil now and would switching to synthetic ol make a difference?

mkefrmthed

You try replacing the catalytic converter?? if not that then check oil galleries on heads if that does not solve problem I do not know then I tried to help take care hope all goes well Mike

mkefrmthed

You might have bad valve guides or bad rings maybe an internal leak. how is oil pressure? if it is not high when giving it gas it is cam bearings needs to be around 35-60 psi at an idle. hope i helped you mike

snowprincess

Hello everyone I have a 2000 GMC sierra 1500 5.3 lt that backfires and misses while going down the road at low RPMs when it is high Rpms it cleans out or runs better changed maf sensor and didn't seem to help runs better with it unplugged has anyone else had this problem? I have thought of everything and can't seem to figure out what it might be. Thanks!

elias

you sure you swapped in a good MAF?
does it idle rough in neutral or only while in gear/rolling?
if rough idle in neutral, does it smooth out when you remove oil filler cap? if yes, maybe intake manifold gaskets & RTV-sealant? (even a good MAF can't adjust for an intake leak?)
these are longshot ideas from an earlier GM V8s, maybe not relevant to your 5.3, but just in case... :shades:

socalpools

Hello,
I have a 2001 Chevy Silverado 1500 5.3l 4x4. I am have issues with the engine missfiring. The computer is telling me that I have cylinders 5, 7, & 8 misfiring. I also have fuel coming out of the exaust. Today I have replace all of the plugs. I still had the same cylinders misfire. Then I switched cylinder 1's wire with cylinder 8's wire and still the same missfire codes. Then I swapped coils with 3 & 5, but still we have misfires on 5, 7, & 8. I then checked power to coil #5 at the power harness and we have 14.6v. Do you have any suggestions from here?

1998lincoln

check the engine temperature sensor! If it's failing it's telling the throttle positioning sensor that the motor is cold so it keep's dumping a lot of fuel. So when the gas is pushed it will flood and it will die! Just something to check ! Good Luck.

corkscrew

This link may help:
http://www.obd-codes.com/p0300
Corkscrew

b072786

i have this 6.0 vrotec v8 engine and every time i try to start the engine it wont unless u pump the gas a couple of time im thinking it may be the fuel pump not really sure and advice?

redi_jedi

redi_jedi

I have a 99' k1500 ls 4X4 z71 5.7ltr. My truck dies, anytime, anywhere. Don't matter what the temp is outside or of the engine. Seems to run nearly perfect, plenty of get up, but for some reason it just dies, out of no where, like i shut the key off. I have replaced, cap, rotor, plugs, wires, coil, ignition module, fuel filter, and one of the O2 sensors. Tomorrow I'm going to change the fuel pump regulator. It already had a new air filter that I put in last year before it decided to die and not start, so I parked it. Now its throwing P0430 code at me. The exhaust has always smelled a little off. Not rotten eggs or even sulfor really, just off. Could the low efficiency of a cat conv. make these motors just up and die like this? 8 times out of 10 it fires right back up, sometimes it dies a couple time immediately after that some times it don't. I have been battling this for months, if I didn't still owe the bank I may have pushed it off a cliff by now. Tired of dumping money into it. Some one please help! I like the truck but this is crazy. Oh ya, if i unplug the O2 sensor behind the cat., will it even run without it or if I do this will it just act like it was never there?

ms1378

Hello, asking for some advice, in the past 2 weeks exhaust started to smell heavy of gas and then in past 2 days when idling, motor feels like its missing. Took it by my mechanic and he said # 8 injector may be clogged. Now I notice that as I accelerate my oil pressure gauge raises up to about 50-55. As i slow down or come to a stop oil pressure gauge drops back to 40. Could this the start of computer-electrical problems ?

obyone

What was the oil pressure readings before?

ms1378

The oil pressure sat around 40 to 42..and I've never seen the gauge fluctuate before. I mentioned that as I accelerate it rises...at 3000 rpm its it climbs to 60 64 then as the rpms drop so does the gauge