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Ford F-Series Gasoline Engine Problems



  • nairbnairb Posts: 10
    Have an 1987 F250 4x4, 302V8,4sp. trans., reg. cab. The thing runs fine for the
    first 1/2hr. or hr. of the day, then it starts running really rough in the low RPM's.
    I have to about floor it to take off in 1st gear when I used to take off in 2nd gear.
    The RPM's also fluctuate when idilng and sometimes it will just die driving down
    the road at which this point I switch to the other tank and that keeps me going
    but still runs the same. Checked the timing the plugs, and looked for any bad
    vaccuum lines but can't seem to make things any better. Would appreciate any
    advice from anyone. Thanks.
  • notlobnotlob Posts: 10
    sounds like you could be having some vapor lock problems.
  • mike9408mike9408 Posts: 74
    If this happened suddenly........check to see if you picked up a bad load of fuel. Does it appear to be using to much fuel (black smoke at tail pipe) Check the Air Filter, replace if necessary. CHECK/REPLACE THE FRAME FUEL FILTER, this is more than likely the problem. If this does not fix it, check the vacuum line to the fuel back pressure regulator and the pressure regulator.
  • nairbnairb Posts: 10
    What do you do about vapor lock?
  • nairbnairb Posts: 10
    It's been doing this for about a month and a half so it's not the fuel. Checked the
    air filter and its fine. And according to my Haynes manual, F250's w/EFI have non-
    servicable or replacable fuel filters. Thats what I was thinking the problem could be
    because I do run both my tanks down to fumes quite often.
  • My truck has 142,000 miles on it and recently the truck died for no reason. It happened again about a month later. I replaced the fuel filter and didn't solve the problem. The pump turns on and speeds up as rpms increase. Sometimes it won't stay running, other times it runs like there is no problem. I am so hesitant to take it to the dealership who has misled me in the past. (catastrophic electrical failure) Plus i am hoping to do the repair myself. By the way no error codes
  • nairbnairb Posts: 10
    Went to check my antifreeze in my truck to see what it was good to (protection
    below zero), and when I pulled the gauge out of the radiator neck, it had yellowish
    oil-like residue all over it. I know when you blow a head gasket, the oil on the dip-
    stick might have H2o/antifreeze on it. Is this possibly the same problem? Any
    help is greatly appreciated.Thanks.
  • Was coming home and engine started to lose power. Had to floor board it the few miles home. Since then, it won't start.

    have replaced the coil, ignition module, plugs, fuel filter, computer and distributor. It is getting spark, and gas. (Clynder 3 & 4 were very wet. others appeared normal) Plug wires are have less than 5,000 miles on them.

    Fuel pressure is 40 psi + or -.

    Adding starter fluid does not help. it doesn't hit a lick.

    I have noticed that it attemps to start when first trying to start after sitting for awhile..

    Again, gas is good, spark is good. Any help in this m atter would be greatly appreciated.

  • It sounds to me like your Catalytic Converter might be plugged (if equipped). My Chilton Manual doesn't cover it but that would be my bet if you have done all that you say. Don't know why #'s 3&4 plugs are notibly wet unless those injectors are failing or the back pressure regulator is failing some how. But raw fuel going into the catalytic converter is a major cause of converter failure. There are test procedures outlined in Haynes repair manuals covering your truck. The manuals are only around $20.00, most of the time can help at least a little help although sometimes are a bit hard to follow or might have a little incorrect information, using good judgement in this case is necessary. Good luck, and please post your results. Thank you, Mike
  • I did as the muffler shop instructed, assuming it was a plugged converter. Same thing. 40 + or - psi on fuel pressure gauge. Nice blue spark. Shot a spray of starting fluid in it and still nothing. I felt sure it was a plugged converter but apparently it wasn't. the only thing i haven't checked is compression but engine turns like it has compression. (Doesn't spind over wildly) Even if it wasn't getting gas, it should have hit on the starting fluid. I have started engines on WD-40 or at least assisted the starting.

    Normally, it will try to hit after sitting for awhile but this morning, it didn't even try to hit this morning.

    1986 efi Ford F-150 with about 140K miles.

    Help Please,

    ernie in Virginia Beach
  • About the only other thing I can think of is "Timing" Check ignition timing. Roll #1 cylinder up to top dead center on compression stroke, then check the distributor rotor to be sure it is pointing at #1 cylinder. If this is ok, the only other thing I can think of is that the timing chain may have jumped. (hopefully not) You might run a compression check to find out if this is the case. Also, check the crankshaft position sensor (wires etc).
  • Ok, you have me there. Is there one on the 5.0? If so, where would it be. I'm about ready to set fire to it. :) Jumping timing did occur to me but it just doesn't act that way but things have changed in my 74 years of shade tree mechanics. I will do just as you suggest on the timing and compression.


  • notlobnotlob Posts: 10
    I had a similar problem back in the 90's with a Chrysler, It turned out that I had installed some special plugs that would fire much hotter but they were failing to spark even though they were getting juice from the distributer. I installed the correct plugs and the problem went a way. I would check the timming also, the wet cyl. could mean the valves a out of synk. Alex
  • Ernie,
    The Crankshaft position sensor is located on the vibration damper. Could be just a wire has fallen off of it or a crack or short in the wire. Look for the wires running down the block to the vibration damper. Ernie, do you have or know someone who has a "Code Reader"? This could narrow down the search. Also, purchase a Chilton repair manual, available at most parts stores. And Read, Read, Read...
  • Hey guys, thanks. I have it parked out in the cold and will attempt it again when it gets warmer. It is my grandson's and he said he was driving it and it just lost power and he had to floor board it to make it home. I have drilled two1/4 inch holes in the exhause going into the converter and that didn't help. It doesn't feel like there is and suction when you have someone turn the engine over and I put my hands over the throttle intake. I would have expected there to be a suction like we used to have when choking a carb by hand. a plugged converter would do cause this but,,,, I still need to make sure I have compression and that the timing is still on. Cold weather is holding me off now. I will just give my grandson my truck and try to fix his when i can get a couple of warm days. again, it has fire and it still won't hit a lick when spraying starter fluid in the intake. It is like the engine is not sucking the air/starter fluid into the cylinders. Maybe a broken cam shaft could do this?????

    Thanks ernie
  • I understand about the cold weather. Did you hold the throttle open while you covered the throttle body opening with your hand? It sure sounds to me like the valve timing. Do your compression check, but I am sure it is the valve train. Probably a broken chain, or jumped chain. Let us know.
  • wvrdwvrd Posts: 5
    sometimes under thottle i hear a whistling noise anybodyelse have this problem
  • i get the same whistling but when its like 35 degrees out or lower, it goes away when i let off the gas or punch it, but it always comes back, its very annoying.
  • I have a 1997 F-150 that Has a yellowish Cream on the oil filler Cap. it is not on the dip stick though. What does that mean? it smells slightly of Gas to and I am not sure if that is normal for a gas engine or not. I have owned my truck for almost 3 years and this is the first time I have seen it. when I went and had the oil changed 4 Days ago they said it was moisture from the engine not getting hot enough to burn it off because of short trips.. if thats the Case how come I had not seen it before the last two Winters. and the truck runs no different then before I had seen the cream on the oil cap I was told to put heat in with the Gas and that should clear it up and it has not. besides Constant Oil Changes every time it gets creamy ( witch I cant afford on my Budget). What are my other options to repair it on a part time minimum wage income??
  • Sounds to me like your pcv valve has stopped working. It is easy to check, just pull it out and shake it. If it rattles it is probably ok. But while you have it out go ahead and wash it in solvent (or kerosene), make sure it rattles with a good rattle sound (if that makes any sense). If you cant get it cleaned, buy another, they are cheap. Let me know how it goes.
  • notlobnotlob Posts: 10
    This is a sign of water in the crank case. I would make sure that you do not have a cracked head or a blown head casket. alex
  • Everytime I saw creamy oil it was a blown headgasket (Anti-Freeze in the oil).
  • Since it got cold this winter the truck will start up then shut back off, unless you touch the throttle. As soon as you leave off it stalls, no idle. After it's run awhile to operating temp it usually run ok. No codes on my scanner. I tested the TPS with an ohms meter, and it icreased smoothly not eratic. Any suggestions, thank you!

    Also, it has 103,000 miles and we keep up on the maintance. This is the first trouble we have had. This truck is usually sitting and used for hauling, and some trips etc.
  • notlobnotlob Posts: 10
    this happened to me also, I drive a 04, F-150 with the 5.4 3 v. It turned out that the ETB on the throttle valve intake was the problem. Alex
  • You were a little unclear if this creamy stuff is re occuring on a regular basis or not. There are a number of possibilities;

    (1)Moisture like the oil changers said. Ford trucks do this a lot.

    (2)Blown head gasket or micro crack in cylinder head or block.

    (3)PCV valve faulty

    If some moisture just got caught up and mixed with the oil over time, your Ford does have a reputation for this. Buy a bottle of liquid not spray Berrymans B12 carb cleaner (pint) and poor into where the oil goes. Drive arround for at least 40-50 miles and then change your oil. Wipe the excess creamy stuff of your cap.

    If it is a blown head gasket there is a product called Blue Devil Block Sealant availible at NAPA. The thermostat has to be removed and you have to follow the instructions on the bottle, but it works real well in sealing blown head gaskets and cracks. Pay a mechanic that has done this before. I have a 98% sucess rate with this product on vehicle that will run for at least an hour even though they have a blown head gasket. On vehicles that have a blown head gasket but do not over heat, it has worked every single time, 100%. Good luck!
  • This truck doesn't have this part. The manual only goes to 2002, so they must have started the ETB in 03. Thanks!
  • If the oil is creamy or yellow and the oil level goes up usually thats when there would be a blown headgasket, or like you guys said before a cracked head, or waterjacket would do this also.

    When you checked the oil was the level above full, and were you low on anti-freeze? That will tell you if the headgasket blew. That happened to my brothers jeep, he replaced the gasket and his levels are good and the yellow is gone in the valvecover.

    I hope this will help?
  • raspyraspy Posts: 3
    91 f150, 4.9 I6 w/5 sp -187000 mi.. over all truck runs good for age and milage.BUT! when truck is allowed to warm up a while you go to drive it and after 5 mi. or so it will start to miss/bog down like its dropping spark or losing fuel. if it stalls it will not restart right away. and it doesnt always do this either. usually a couple days in between. the first time this occured i opened the hood and found the ps pump cap loose and it had sprayed some fluid on the coil and its connecter clip. a few dayes later i put new plugs cap rotor. made no difference but i did notice the distributer was extremly loose and was out of time. i reset by ear which corrected the loss of power ive had ever since ive owned the truck but has had zero impact on the running crappy and stalling issue the local shops wont touch it cause they say it has to be not running for them to find the problem but when it dies by the time i get it in town to the shop it will restart on its own. Any advice on this matter would be greatly appriated
  • notlobnotlob Posts: 10
    find another shop. check for vapor lock. but it really sounds like you need a complete tune-up. Alex
  • Sounds exactly like my 1991 2 1/2 years ago. I found it to be the wire connectors that attach to the fuel tank. I finally cut a hole in the bed of the truck (as an access hole for future problems) marked the color code on the fuel tank. Cut the slip on connectors off of the wires and re-connected them using wire Kern's (available at any hardware store or electrical supply store). Mine of course is a single tank (rear), if you have duel tanks and this problem is on either tank it may be another problem.While you are checking out the truck, check the condition of the vacuum hose running from intake plenum to the return control valve (fuel return control valve). If it is cracked or anything, replace it. Please let me know what you find in the end. Just enter here your findings and it will automatically come to me. Mike
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