Thread: car shakes

2000 pontiac gtp s/c, car shakes on acceleration, and sometimes idle not sure whats causing it i replaced wires and plugs and it went away for a few weeks now its back. i replaced the maf, and checked for vacuum leaks so far so good there. one post said maybe o2 or cat any ideas where 2 start. autozone said coil packs but I think they were looking for a sale...

No check engine light?

no I had the car in for a new multi function switch and i think they dis connected it cause it should be coming on, that was a year or 2 ago.

scanned codes p0204 and p0304 so cylinder 4 misfire and injector #4 problems, plugs and wires are only maybe 6 weeks old and a new fuel filter is on, also as mentioned new maf like 5 mths ago. was going to start by changing the wires around then coils, then injectors, could a bad cat be causing this ???

need a new injector

ok ill grab one tomorrow and let ya know, or do a swap test first.

yea swap an injector over from a different cylinder and see if the misfire changes cylinders

yep bad injector, replaced and its not popping any codes runs good, but slight miss hap while trying to torque the fuel rail nut on the bolt if friggin snapped off, now what. it is fit tight would 3 be good to run on it or no, or can i secure it down another way anyone ever had this before. and thank you for your earlier help .

I actually did the same thing when i took everything apart to clean and paint it. my fuel rails been held down by 3 bolts for a year now. no leaks or anything. long as the o-rings are in there good they hold it down. if youre really worried about it though, only way to get that out would be to drill out the bolt and retap the hole, unless you can get lucky and get it out with a screw extractor set.

k, It looks pretty tight so for now ill keep an eye on it. I might try and get the screw out never did that before so who knows. I want to thank you for replying, this site is awesome.. closing in on 190k hoping for 200ish has been a great car and just now 10 yrs later now starting to nickel and diming a bit.