help again!!!

[bluchevy]

ok the problem im having is that the truck runs and idles up and down until i unplug the map sensor or unhook the vaccum line to it. Then it idles fine and will run i dont understand the problem? Every sensor on the engine is new along with a new ecm and the head gasket was recently done idle air control is also new also the fuel pump is new. no vaccum leaks and good compression ive had several mechanics up here and none have figred it our yet. reallly need help.

 

[bizzo15]

Just a stab in the dark but maybe the new map sensor was bad out of the box? Really hard to trust any of the new cheapo electronics coming out of china these days.

 

[bluchevy]

not that because i tried one that a freind of mine pulled off his running rig and also bought a new one so i doubt thats it also fogot to tell you all its a 1990 with a 5.7 tbi

 

[dirtyhick42]

Ecm not tuned right maybe? If it's new and you didn't have the problem before that's the only thing I can think of.

 

[bluchevy]

doesnt the prom keep alll the info?

 

[bluchevy]

anyone got any ideas?

 

[71 cuda man]

I'd think dirty hick is on the right path look at the ecm

 

[bluchevy]

i dont know what caused the problem the truck had many problems befor and ive been working threw them but is there any way to know my ecm is the right one and is there anyway test it

 

[dirtyhick42]

take an ecm out of a stock truck that matches yours and see what happens

 

[94_C/1500]

Just a shot in the dark, when the motor is cold does it run fine?