HELP 5.0 giving me trouble again October 24, 2006, 07:30:14 PM 88 t bird with 5.0 aodguys i had a problem with the studdering and stalling of the car and i sort of fixed that with a new motorcraft tps and motorcraft IAC . But i still get this just one stall that comes when i first start up the car. It stays on for a while then shuts off and after that i turn it back on it stays regular. After that say im on the street driving and then i stop at a light, it has like a "pupping" vibration and the car has gas . What could it be?? MAYBE fuel pump?? Also what should the rpm be when the car is at idle when hot??sorry for the long explanation. Quote Selected
ditto Reply #1 – November 07, 2006, 10:26:29 AM I'm having this same problem on my 87 Cougar XR-7 5.0L/302 V8. I am suspecting it's the fuel pump, but I need to get a fuel pressure test done. When I start it up in the morning, it WILL NOT stay running, but after driving it for 40 minutes at 70mph, when I come to a stop, it idles ok and will stay running. Then after I've parked it for awgile, and I go to start it again later, it won't stay running again at idle, I have to pop it into N when I come to a stop and keep my foot on that gas pedal to keep it running. It also idle erradically when I have my foot on the gas in Neutral, it idle up and down on it's own..... sorry, i'm not trying to hijack your thread.... I've replaced plugs, wires, cap, rotor, iac, cleaned the TB, check for vaccum leaks, etc. Quote Selected
HELP 5.0 giving me trouble again Reply #2 – November 10, 2006, 01:56:27 AM Check the plastic connector section of the IAC for the following code: 3D. If you see this code, it means the IAC has an internal diode. Our cars came with an IAC without an internal diode. You will need a VO meter to check polarity. Once you have the polarity of the IAC, check your harness connector to ensure that it matches. If your harness has the opposite polarity, the IAC will not function and will cause trouble especially when the engine is cold. If it does not match, fix it so it does. This should solve your issue. If it matches, the issue may be something else. Quote Selected
HELP 5.0 giving me trouble again Reply #3 – November 10, 2006, 10:08:11 AM Quote from: GreyWolf30;112670Check the plastic connector section of the IAC for the following code: 3D. .... This should solve your issue. .Thanks! I'll check it out right away. Could this also be EGR-related? Or O2 sensor? It's weird, because when the car is cold I have to give it constant gas for 5 minutes or so until I get 2 bars on the digital temp gage, then I can drive it and it idles fine when I come to a stop. But if I turn off the car, then start it back up again, I'm back to the idle problems, even though the car is warmed up and even though it was fine right before I turned it off, even 25 seconds ago.... Quote Selected
HELP 5.0 giving me trouble again Reply #4 – November 11, 2006, 01:07:26 PM Well, I just checked my iac plastic connector and it had "4D" stamped into the side. So I went down to NAPA and bought a new IAC for $60. The new one has "6D" stamped on the plastic connector. I put it on, started the car, it idled UP and DOWN, UP and DOWN, for about 90 seconds, then it idled down too low and died. I guess that wasn't the problem. Bummer! Anyone have any ideas on this problem? I'm wondering if it could be O2 sensors. The computer is not throwing a code, at least the service light is not coming on. Maybe there are some codes in there, but I don't know how to pull them without a code reader. Quote Selected
HELP 5.0 giving me trouble again Reply #5 – November 12, 2006, 09:58:24 AM QuoteMaybe there are some codes in there, but I don't know how to pull them without a code reader. Quote Selected
HELP 5.0 giving me trouble again Reply #6 – November 14, 2006, 01:36:54 PM Quote from: Gw-west;112885Well, I just checked my iac plastic connector and it had "4D" stamped into the side. So I went down to NAPA and bought a new IAC for $60. The new one has "6D" stamped on the plastic connector. I put it on, started the car, it idled UP and DOWN, UP and DOWN, for about 90 seconds, then it idled down too low and died. I guess that wasn't the problem. Bummer! Anyone have any ideas on this problem? I'm wondering if it could be O2 sensors. The computer is not throwing a code, at least the service light is not coming on. Maybe there are some codes in there, but I don't know how to pull them without a code reader.Did you check the polarity first (before buying the new IAC)? The "D" is supposed to mean that it has an internal diode. Quote Selected
HELP 5.0 giving me trouble again Reply #7 – November 16, 2006, 03:54:44 AM I have an O2 sensor not even working and the car still starts and runs. Last time I had a problem with a fuel pump the car just shut off and wouldnt start back. Ive had problems with stalling and stuff when that hose in the tank that hooks to the top of the fuel pump went bad.sounds like its just running bad if its not pulling any codes have either of you two by chance tried a tune up? Quote Selected
HELP 5.0 giving me trouble again Reply #8 – November 16, 2006, 09:41:09 AM Quote from: Master_xzavior;113896sounds like its just running bad if its not pulling any codes have either of you two by chance tried a tune up?Yes, I did a tune on on mine when it started having this idle problem, I put brand new plugs, wires, cap, rotor, fuel filter, air filter, pvc valve, IAC valve, and added fuel system cleaner to the tank. After all that, I expected the thing to run great, but no such luck! Now it's just sitting in the car port. I will check the polarity on the IAC connector, and I will check to see if there are any codes in the computer too. But beyond that, I may end up taking it to the shop (it will be the first time in 10 years!) :disappoin Quote Selected
HELP 5.0 giving me trouble again Reply #9 – November 17, 2006, 08:40:17 PM Do this when car is cold. Remove positive from battery, wait a few minutes, reattach cable then start engine. Try to keep the car running for a couple of minutes or as long as you can within that time. Now, take the POST codes. What are they? Quote Selected
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