• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Car starts , runs rough , sometimes dies , then smooths out

D

Davey1234567

New member
I have a 04 Gtp n my car will start then run rough sometimes dying then straightens out . I've cleaned the throttle body n Maft . Seemed to help but my issue doesn't happen every time . There's no consistency when this happens also . I have no codes also. Has anybody had similar issues ? I read a few people had this issue with the older gtps but not a 04 . I also seem to get a little hesitation on wot .. Ideas ?
 


I would have said TB and MAF cleaning are in order first, but that was done.

Next would be to check spark plugs and replace is never done before. Never hurts to check fuel pressure either, though that seems more unlikely.


Where at in MN, could be close to me maybe.
 
I just had the motor out and resealed everything from rear main seal cover to valve covers , oil pan etc . I did put new plugs in but I got them from orielys and they looked them up , The car is stock also . I just took it out today and it misfired 4k and up if I floored it . Cel flashed n got code p300 ..
 
Last edited:
flashing cel is misfires. clogged cat or bad plugs, maybe a plug wire is crossed up, double check them. the plugs you want to use are iridium plugs, not platinum. 3800's dont like plat's at all. if thats what they gave you. double check them as well.
 


I like copper core plug's better than iridium. the last set of iridium plugs I had didn't last near as long as they were advertised to.
 
sounds like hes stock, so copper is not really needed. copper only last 15,000 miles tops. so if you dont mind a tune up every year the 3800 loves the copper plugs.

copper core plugs are also silly cheap, less then $2 a plug most of the time.
 
My guess is your problem could be a vacuum leak. Get a can of carb cleaner and spray around all of the gaskets while the car is running. I deff' second checking your plugs, cat & EGR valve. Vacuum lines too.
 
I have my laptop that can scan all cylinders for misfire to help determine what ones it might be, I also have a spare ICM laying around if needed for testing.

But I agree with the other, what plugs did they sell you?
 
Ok thanks for the tips guys but something bad happened today with it . I decided to do a couple more hard pulls so maybe it would set just a single cylinder misfire or just another code in general to help and in doing so the engine started knocking , sounds like I got a rod knock . When I had the oil pan off all connecting rods had alot of side to side play but not up and down . Also all seem to have about the same amount of play . So I didn't think much of it . ( when I had the engine out prior ) Question now is I have so much time and money into it since I bought it what are my options ? Can I toss some standard bearings in it ? Do people get these rebuilt ? Find s boneyard engine ? I'm thinking bout just putting it on cl and seeing what I can get ...

- I know they were ac Delco and irdium
 


if the bottom end is knocking the cheap way is a junk yard engine.

you cant just slap new bearings in these engines with out machine shop work. the shop costs will cost more then the jy engine.
 
Pull the valve covers and make sure everything is good under there, would suck to swap the motor when it was just a broken spring/bad lifter/pushrod or something much easier. Unless you know 100% no doubt it's a rod.

If it is, then junkyard motor without a doubt, sucks you just bought all those gaskets on your current one. I just spent close to $200 in gaskets for the L36 going in the wife's SE, **** adds up quick.
 
Ya sounds like a rod n by looking at the balancer can almost guarantee it's a rod , engine doesn't really miss , n I think would if a top end component was bad ... But anyways what would this far be worth as is so you think ?
 
by looking at the balancer? whats it doing? a bad balancer will knock around and could make the car run poorly.

take the belts off see if the balancer moves by hand most of the time you can see it cracked around the outer edge.
 
You must log in or register to reply here.
Back
Top