Need Help pulling codes on 96 F-150 5.0L...
 

Well it will not catch an idle but if I hold my foot on the gas pedal it will run fine and I can get it to catch an idle sometimes. Already checked the voltage on the IAB as well as the resistance it is fine, TPS gives me some weird readings so it may be that but doesn't make sense that it runs fine except at idle.

I did a resistance test on the TPS and with it closed I get 750 ohms, fully open 3.68ohms but when I open it slowly it shoots all over the place anywhere from 1000-2400ohms, do you think that is the issue? It wasn't pulling any codes but now I do get a solid check engine light?

Can anyone help me out on this? Thanks guys...

Chris "PKRWD" I sent you a e-mail...this is after that.

Didn't recognize the name in the email. Sorry. I was in a hurry then, too. Yes, your TPS sounds bad. The rheostat is worn. Testing it for resistance is the best way to check it, and your results mean that the rheostat has several worn spots on it. The engine should run fine until it hits one of the bad spots. Then, the ECM doesn't know what's going on. Replace it with a new one, but make sure you reset the ECM afterwards (disconnect neg bat cable, turn on headlight switch for 10 minutes to drain capacitors, reattach bat cable), and then do a re-learn for the ECM:

idle @ 1000 rpm for 1 minute.
key off for 10 seconds.
idle @ 1000 rpm for 1 minute w/ a/c on high, headlights on high, etc.
key off for 10 seconds.
idle @ 2000 rpm for 1 minute.
key off for 10 seconds.
idle @ 2000 rpm for 1 minute w/ a/c on high, headlights on high, etc.
key off for 10 seconds.
test drive.

Take care,
~Chris

I thought that was a little short;) Well I ordered a new TPS, can't beleive no local place had one in stock, I live in PA home of the offroad truck..lol

Shame I can't use the same TPS that the mustang uses, it is a different ratio I have 2 of those laying around.

Thanks for the help,

Rick!

Rick, I am sorry about the email. I had been away from the Mac for a few days, and was going through a couple hundred emails when I came across yours. I get alot of private emails asking for help, which I don't mind, but when I don't recognize the sender, or they say "My Mustang runs crappy, what do you think is wrong?", I tend to brush them off. Please accept my apologies!

Take care,
~Chris

No Problem Chris, figured you were just having a shitty day and didn't feel like answering e-mails...I brushed it off and kept checking things, pretty sure it is the TPS hope to find out tomorrow when it comes in. Shame you need to pull the TB off to get to it..oh well.

I'll let you know if that fives it, if not I may buy a scanner, could come in handy in the future. Although all the scanners I see only go to 95 with a EEC IV processor, I'm pretty sure that is what my 96 truck has so I assume it would work right? If not I'll break out the old jumper wire and test light...

Most, if not all, 1996 F150's are OBDII, which require an OBDII specific scan tool. They can't be jumped with a paper clip and a jumper wire. A decent OBDII scan tool will cost you between $200 and $400, but can be used on any 1996 and newer vehicle, foreign and domestic. The better ones also give you the ability to view a live data stream, so you can read each sensor as it's operating. I use an OTC Mindreader, which I love. Here is some info on it, just to give you an idea.

Take care,
~Chris