I know I posted recently about my tps issues but the problem has not not been remedied. Im hoping you can help me out. Heres what I have. 2003 1500 QC 4x4 4.7 CAI Fastman 98.5mm TB Superchips programmer E# plugs and cat back exhaust. Sypmtoms: I replace TPS about evry 4-8 weeks. I get them at Oreilly's. The truck will not idle correctly but once I pop a new one in im good to go for a while. Now all of a sudden while on the highway the truck will shift to neutral till about 40 mph and then lock into 2nd gear. I limped home used the programmer to read and reset the tps code and replaced the tps. All was fine for about a week. It did it again. This time the local dealer tells me I need a factory TPS that the ones from Oreilly are cheap. BTW when I removed the old TPS sensors and move the potentiometer with a screwdriver it feels gritty, like the bearing or springs are shot. The new TPS feels much smoother and tighter than Oreilly's. I replaced my Idle Air Controller yesterday which had both orings shot and also replaced my PCV valve and ran a vaccum test and that came back normal. Ive looked for loose connections,wires bare, and tapped everywhere on the engine even the PCM. The truck will idle fine for a while and than start to idle erratically. If you goose the throttle to about 2500 rpm and let off quickly the rpms drop to about 2-300 and sometimes it goes back to 600 and sometimes it dies. Im stumped. What am I not looking at? I know its gotta be something simple or electrical. BTW the Superchips programmer will read many different parameters while the engine is on so if that helps let me know. Where have I not looked? TB is tight on the manifold although there is no gasket. Wasnt one when I replaced and didnt get one from Dan when I got the Fastman plus the vaccum was ok. On the highway last evening it seemed run well untill I came to a stop or in park than the idle jumped up and down by 2-600 rpm. Any ideas??

 

thats a very large diameter for a throttle body are you sure you typed in the correct size...to start with? i see you dont have a intake either you should really pick one up running a bored tb and exhaust system you really need it to be able to suck more air check the very first page of the 287 club i have a link for an exceptional intake with a heat sheild and very good filter...

 

Good call yeah I typed that wrong it's a 68.5mm and yes I am running a cold air intake system. Any ideas what could be causing my problems?

 

Have you tried to see if you took the SC tune off the truck if it still does the same thing?

It sounds like it's getting too much power somewhere and frying from the inside. I maybe wrong. Have you checked to make sure the fuse for the TPS is what's recommended in there and that noone has changed it out to a higher amp?

 

yes ive taken the program back to stock and that didnt make a difference. I hadnt checked the fuse for the tps. Ill look at that. Like I said the idle is wacky and ive been replacing one thing after the other trying to narrow it down with no fix as of yet. It sucks to not know what is wrong or where to look.

 

Does anyone have any suggestions on where to look next or ideas of what could be going on with the truck?

 

try putting thye stock throttle body back on, my modern muscle TB will cause mine to idle erratically from time to time

 

I dont have the stock throttle body I sent my old one back to Dan for my core charge. Any other ideas or things I can try out?

 

When you replaced the TB, did it get a gasket or o-ring to seal it to the manifold? Check with brake cleaner around manifold connection when the engine is at full temp. Also check for any leaks in the connection tubing for CAI to TB. Have you disconnected the battery and allowed the electronics to reset. Especially after the TB and TPS replacement?

Its seems possible that as your engine heats up, you may be getting a vac leak.

One other REALLY dumb question, BUT----did you check to make sure you didn't leave a shop towel in the intake anywhere? I know its sounds dumb, but it's happened to me too.

You might also pull the TB off, and check the smoothness of operation to be sure there isn't anywhere the butterfly rod isn't hanging on anything---just some thoughts

Good Luck!!

 

HA!! Thats happened to you to huh?