Thread: GT Sputtering under load- only at idle and slowing down

hey guys and gals, 25 male from mass here. single dad 4 kids lol. ok heres my problem. I just got a 2000 grand pix gt. really nice looking car but thinking it wasn't maintained vary well. but its all i could get. 500 bucks.. so im to fix it myself. i dont mind though. i just have to pick and chose where to start with money.. ok so the car ran great for the first few days... then just now im down the DMV getting the reg.. when all of a sudden it starts to sputter at low rpms. when i start to go , it smooths out. i did how ever notice like a slight wining noise when i give it gas.. so i took it down to the ol' auto zone. engine light was on since i bout it a week ago.. i was told evap leak when i bought it. so they plug it in and give these code. :
p0442( evap) p0301(misfire in #1) and p0341 (canshaft sensor) so being as i can only do one at a time, and at least need the car to run like it was a week ago. where do you think i could start to do so.

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Also noticed today driving it to work and dropping off the kids, it just would sput and die while driving, I pull over and start right back up.... Did this 3 times on a 20 min drive, just out of no where to.. But would start right back up no problem then go just fine..

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my trac off light turned on and the rpms dropped to zero while driving; few minutes later would stall; started up right away no problem. replaced crank position sensor. you need a harmonic balancer puller thingy; took to my shop about 1.5hr and $80 parts.

Just got done work and heading to autozone to get the camsaft sensor. Hopeing it will get me to another week to do plugs and wires.. Ill keep ya posted thank you so much

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ya fixed er right up.
ive got bigger problems now!! im getting a ton of shuddering and no power. changed TPS, cleaned TB, changed plugs, changed both O2 sensors. thinking now it might be either TCC, ICM, or cat. im tired of guessing. taking it to shop monday morning.

Well replaced the cam sensor... No change... Didn't have enough for plugs.. Think it would kill it to drive a week?

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I have a 99 gtp and have gone through the EXACT same thing you have, first thing, did you do the crankshaft position variable relearn after replacing the sensor? If not start there, if so, you'll be right where I am, I had cat and "u-bend" cut out, I've replaced plugs and wires, and I'm still having a massive misfire/stalling/sputtering issue, taking it to my local gm dealer, it'll be pricy but I'm sure they'll find the issue, anyways, I will keep you posted on what I fin out if you would be so kind as to doing the same, I've been chasing this problem for two months and throwing money at the wrong stuff, as I'm sure you have too and would rather not anymore, chow for now

Oh and to answer your question about driving it, I've noticed a massive loss in my fuel mileage so mine has been parked, I'd suggested not risking it getting as bad as mine where it stalls at every red light and just leave it parked... Personal preference

Thank you so much! plz do keep me posted. I didn't even know about the sensor relearn.. How whole I do it ? I replaced both sensors just cause I found on the 3.8 they piggy back on each other so one can fault the other. Plus I found a video when pulling the belt and the water pump pully I found them pretty easy to replace..
So after that didn't solve the problem I switched the coil packs to see if the problem moved. I scanned again. Same misfire..
So I got a few bucks and replaced #1 plug and wire! Seemed to have smoothed it out.. Going to get it scanned again and see. Will keep ya posted..
I did find that I think the valve cover gasket has a lot of oil sweat on the bottom side.. The plug when I pulled it was covered with dirt and oil?? So I gave the valve cover a little tighten.. Thinking I may do that replace real soon. And the rest of the plugs. They look like the original wires, numbered and all..
So well se how it does. Plz keep me posted as well

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I replaced the crankshaft position sensor only... And my car hasnt thrown a code for anything else since I've owned it, yet its performing so erratically that I can't even drive it to the store without it stalling and burning a crap load of gas... What can cause up to 30 misfires on random cylinders? I can't figure it out

The relearn is done on a diagnostic tool, it's call a "crankshaft position variable relearn"

Yes I've replaced plugs wires and fuel pump since the crank sensor

I've done a cat delete and replaced my fuel pump already as well