Magi666

I have a GSL-SE which is having bucking problems whenever the engine is under a decent amount of load (going up a hill or highway speeds) and full throttle. It seems to accelerate better under part throttle. This only happens when the engine is warmed up; if it isn't fully warmed up the bucking doesn't happen. When it starts to happen the engine also won't go past 4k rpms.

I thought it was the TPS because when testing it with a multimeter I could get it to 1kohm when idling but every ten seconds or so it would go all over the place. Also, with the throttle wide open it would only get to about 3.4kohms. I replaced the TPS and the new one seems to be working fine per my multimeter but the problem still exists. Here is a list of things I have done or replaced recently (not necessarily because of this problem):

New spark plugs and wires
Made sure timing is correct
New air filter
New O2 sensor
New fuel filter
Replaced TPS

Any suggestions are appreciated!

85 FB

When you installed the TPS, did you adjust it properly? There's a thread on here that tells you how to get a couple LEDs from Radio Shack and adjust it. I've done it, it's really easy. That is, if you hadn't adjusted it properly, tho.

Magi666

I believe I have, I followed the multimeter route not the light route. From my Haynes manual it says at idle it should be 1kohm and with an open throttle it should be between 5kohm and 6kohm. I did adjust the new one to 1kohm at idle and at open throttle it was getting about 5.6kohm.

Magi666

Okay I have an update. It is worse now, almost to the point where I can't drive the car. It won't rev past 3k in neutral and when driving it starts bucking and won't accelerate past about 2500 rpms. It does it with the engine cold now. I checked the AFM and made sure it is working properly (flap opens just fine and the electrical connection is getting the correct open/close readings per Haynes manual). I also replaced the fuel pump and that didn't help.

I did notice that after shutting off the engine exhaust will keep coming out the tailpipe for about 15 seconds after the engine is off. Do you guys think the exhaust might be clogged causing these problems? Near as I can tell the exhaust is stock with what looks like a precat coming off the headers to the main cat. Any advice is appreciated.

Crit

iTrader: (6)

Sounds like a clogged cat to me. Drop the main cat from the precats and rear pipe and see if the car drives better. You can drive to a commercial park on a weekend, drop the exhaust, and run open header around the parking lot if you're worried about neighbors.

rotarycrazy

iTrader: (8)

and if that dont work try changing your fuel filter and clean out the little strainer that should be in the fuel line right before it goes into the fuel pump if its cloged up it will make it to where it is not getting enought fuel and start cutting out thats what the problem with mine was I ended up droping the tank and boiled it with acid.

Magi666

Thanks everyone for your help, I appreciate it. I just want to update this with what fixed my problems. The cat was clogged and after replacing it I was back to the original stumbling problem when the car was warm. It ended up being the pickup in the distributor causing that problem.