Just wondering if anyone can help me out, this problem is driving me nuts. I have a 1996 F150 4X4 with the 4.9 six and a 5 speed. I bought the truck brand new and currently have 142,000 miles on it and this is the first problem with the engine. When I drive it, and shift, the rpm's will stay where they are at, and even slightly rise for a few seconds then drop down to normal. For example, I shift from second to third at 2200rpm, the rpm's will remain there and even go up a few hundred when I let off the throttle and push in the clutch, if I coast with the clutch in and foot off the throttle, in about 3 seconds they drop down to where they should be. It only seems to do this above 1500rpm, below that everything runs normal. The truck runs and idles like new, I checked everything to make sure nothing was binding, and lubricated what I could. I used a code reader and it spit out code P0122: Throttle/Pedal Position sensor A circuit low Input. I replaced the TPS and cleared the codes but it does the same thing and the trouble code reappears. Anyone have any suggestions?
Any help is much appreciated.

Thanks,

Craig

 

Lift your foot off the gas maybe? lol
I was thinking the TPS, but if you changed that it almost has to be sticking on the butterfly rod.

 

Yeah, I know, it's a great way to learn how to speed shift!!
I'm going to pull the throttle body off and really go over it, check everything to make sure nothings worn and clean it really good. I checked the price on new throttle bodies and factory replacements are like $400-$500! Ouch.

Thanks for the response.

 

Have you checked the release bearing. Mine went out and the samething was happening.

 

Sounds like the same thing my mustang used to do between shifts. Also when I would be slowing down to a light and through it in nuetral for the last say 50-100 yards, the rpm's would hover around 2200 until I came to a complete stop then they would go down, eventually it got to the point where the rpm's would just stay at 2200 and it drove me nuts. I think it was along the lines of dirty or sticking I.A.B. (idle air bypass). Ultimately I made a block off plate and pulled it off. Try disconnecting it and see if it still does it. If it stops, try pulling it off and cleaning it. I believe it's an emission control part and is covered under warranty for 100,000 miles (I think that depends on the state in which you live). IMO, I would'nt pay $100 for that thing, car ran fine without it, still does, even with the new auto tranny.

 

Hey Mike12pt,

Thanks for the reply, but I think I fixed the problem. It ended up being a bad wire to the TPS. I only had .4 volts coming into the TPS from the ECM and it's supposed to be 5 volts. I did a lot of tracing and checking of wires and I really never found the exact location of the problem because it was in one of the main harnesses which are wrapped up tight. It's so cold here now that I didn't want to mess with the harness anymore, so I just ran a new wire from the ECM to the TPS and everything seems to be fine, no more error codes and the truck is running great once again.

By the way, nice rides listed in your signature. I have a 2003 SVT Cobra sitting in the garage waiting for the loooong winter to get over with. It has run a best of 12.5@112 with a Magnaflow catback and a drop in K&N on the stock tires. I just bought a Predator hand held tuner with a custom tune for my xmas present, so I'm patiently waiting for spring and a dyno session to see if I can improve on the 401rwhp, 380rwtq it put down this spring.

Thanks again for the response.

Craig

 

Glad to hear you fixed her. Thanks for the compliment, I just put a link to my gallery on my sig, if you'd like to check 'em out further, there's some neat off-road pics too. I wish I could afford a 03 cobra, it's a great car and an even better starting point for building a faster one (much stronger block, steel crank, manley rods, forged pistons, 4v heads, stock supercharger, man oh man that's good stuff).