HELP - Grand Am revving/idling at 3000 rpm
Hi, I hope someone can help. I changed the motor in my 88 grand am quad 4
dual overhead cam and now when you start it it runs at 3000 rpm's and I
can't lower it. The motor I replaced it with is a 91 dual overhead cam 2.3.
I changed the air flow sensor, throttle body positioning sensor but I used
the thottle body from the 88 quad 4. The motor runs fine except for the
high rev. There is no vacuum leaks. I am wondering if the fuel rail system
has more fuel pressure from the 88 compared to the 91. It seems to be
getting more fuel than required when you put your hand over the throttle
body to try and starve it for air it still doesn't idle down. I don't know
what to think because I was told by GM that this 91 is the same motor
except I had to use all the sensors and throttle body off my 88. If anybody
can help diagnose this problem it would be greatly appreciated. NOTE: I did
not change the sensor for timing and it's not running rich or lean.