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Stall off idle...

M

mastert429

New member
Someone gave me a 97 grand prix with the 3800N/A that i'm trying to diagnose an engine issue on. It starts right up, and idles smooth as a nut.. but the second you hit the gas, it stalls. if you floor it, it'll surge, then almost die, then surge, then almost die. Seems like TPS to me, but it doesnt seem like it'd make it stall anywhere but idle if it were.. Any ideas?

Someone's removed the CEL light and i cant get it somewhere to have codes pulled.
 


I'd clean the MAF and check for vacuum leaks. A dirty (or bad) MAF will cause all kinds of wierd stuff to happen.

Also, when you floor it are you in Park? Could be bouncing it off the rev limiter (not good) ;)
 
as stated above, check the vacuum lines and MAF sensor. there is a diagram on the bottom side of the hood near where it latches for the vacuum lines. also, check the fuel pressure at idle and when hitting the gas, and the MAP sensor which is on the opposite end of the upper intake, on top of the PCV valve. The MAP sensors on these cars need to sit just right or all kinds of funny stuff will happen.
 
I looked for vaccum leaks and didn't find anything, I checked the tps and voltage looks okay. I tried to get the ecm into limp mode by unplugging the maf and it didn't change the way it acted. I'm thinking maybe a fuel pressure issue since it sat in my yard for so long.

I did get manage to get it drivable once in my diagnosis, but under load it seemed to run lean, and ot did okay until I restarted it.. so maybe the f/p is having some trouble
 
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