Ok, my friend owns a 97 Lumina LTZ with the 3100 v6. (It's the same car we swapped the monte carlo seats and black monte dash into. Neway, a while back (4 months ago) we had a little bit of trouble with the engine. The car would turn on and idle ok, but then it woudln't rev past 1500-2000 rpm's. You could drop the hammer as far to the floor as you wanted, but nothing above 1500 rpms still. Well, we put the OBDII scanner on it , and pulled problems with the TPS (seemed logical). So, we took a trip to the bone yard, found a TPS and took it back home with us, swapped it, tried it, and the problem appeared solved. Well, the car ran fine for 4 months, w/o issues ... until now, when it's started doing the same thing once again. But the difference is now it's not throwing any codes. My friend is at the brink of taking the car to teh shop to get it fixed, (despite howmuch he'd hate doing it) but i was just trying to find out if there's anything that needs to be checked b4 he does. remember, 3100 v6, DIS ignition, believe it's Mass Air fed. It almost seems like the computer is holding it back or something. Thanks in advance.

 

Not sure if this is helpful, but I have had trouble with my TPS and the car didn't throw the code, its possible it may be bad again, only way to test it is to get another TPS I suppose. Seems thats the problem if its the exact samething happening again.....*shrug*

 

Anyone ever stop to think the boneyard may not have been the best place to go for a sensor that is obviously capable of failure?

And I too spent about a month driving around with serious TPS issues until it finally popped a code.. sure, once it popped a code the car ran great, because once it popped that code I popped the hood and went "Hey! Those TPS wires aren't supposed to be melted to the valve cover!"... but obviously it should have thrown the code a month in advance..

Another possibility, since you're not being descriptive of why it won't rev past 1500, is the park/neutral rev limiter...

 

It's not the park neutral rev limiter since htat doesn't engage on those cars until 4k-4.5k. tried it on the lumina (when working properly, and then on the 04 impala and both did the same. Shut her down at 4-4.5k rpm. So, that wouldn't be the issue...do konw about junk yard tps' and the fact that "this is why they're in a junk yard, but everythings worth a shot (especailly iftis' free)

 

You might want to take a lookk at the catylitic converter. If it's clogged then you won't be able to empty the cylinders of the exhaust and it wont rev. Happened to me when mine died.

 

the cat was actually something my friend had thought of as well. I don't really think that it's the cause, but it is a possibility. I'm still kinda leaning towards a bad TPS sensor, might be worth it to buy the new one, and see if it solves the problems. Hopefully we'll get it worked out soon enough, heck i'll be home in a little more than a week, if it's not fixed by then...guess i'll be fixing it. "he's a carb guy, Fuel Injection is his weekest point. Shoulda heard how happy he was when i told him i was thinking of doing the carb swap for the northstar...he seemed uhhh, overly excited." LOL. Thanx for the imput guys, i'm gonna pass it along...keep em comin if ya got more ideas.

 

How many miles does his 3100 have on it? My wife's car threw a code, something to do with the canister purge or something or other... drives good, spools waaaay up if you want it to, I'm wondering if I should worry about my TPS going south. Oh, is the throttle cable on the throttle armature? It came off the track on her car, wondered why the throttle was so stiff and seemed unresponsive, then it snapped where it had rubbed against the throttle body. THAT wasn't very cool. After we replaced it (the cable), it worked great, even had better throttle response, as it was properly on the track of the armature.

 

2_point8_boy beat me to it; I was going to suggest the cat, too. Was the dude's car running very rich before the TPS fix? Catalytic convertors don't like fuel... could've broken up the cat. You said the car won't rev past 1500-2000 rpm's... what happens? The rpm's just stay constant? Or does the motor start backfiring?

If he's driving and mashes the go-pedal, does the car act the same? Like it's dragging a 3000 ton boat behind it? If so, that was the test-drive I took my old friend's 84 2.8 out for... sucker had no power at all. Pretty scary to drive... when I'd floor it, nothing would happen. I suggested the catalytic, but never dealt with a clogged one before so I told him to get a 2nd opinion... he went to his mechanic, and yep, cat was clogged.

If you want to remove the cat for test purposes, if it's a slip fit and won't come off, here's a tip. Slice the slip-fit at the y-pipe lengthwise (parallel to the pipe). Then use a hammer & screwdriver to separate the slip-fit joint. Now, say the cat is fine. To put the cat back on, just slide everything back together, and when you put the clamp back on, it'll compress the widened-and-cut-slip-fit back around the pipe. You'd probably have to use an air-powered cut-off wheel for this... or a die grinder... don't know of any other way to make a horizontal cut in that joint.