What should the idle rpms be on a 88 2.8 MPFI with A/T.. I have a chiltons book but it doesnt say what the idle RPM should be for the 2.8...

 

Hmm.. mine says 500Rpm for manual & Auto is supposed to be 600Rpm. hope that helps.

 

well thats a problm. it wont run below 800rpms.. and its sounds really sick at that ... Sounds good and idles great at 850 to 900

 

Mine idles smoothly with a bit of chop but very little rpm jump. its just the cam mine has. if it wont run that slow it has a vac or IAC passage/motor problem. mine runs 550-600. idles at 1000 till it warms then settles down to that idle.

 

I rebuilt that top half chasing Vac leaks today.. would the IAC give a code if it went bad?

 

hmm not shure. it should but i have had the ECU fail to tell me something was bad even after it stoped working so i cant say for shure. also stock or aftermarket tach? if aftermarket how is it wired in? wire from the coil or clip on the #1 spark wire?

 

before i did the cam and **** my cold idle was 1,300 and warm idle was around 800-900 if that helpslol now my idle is like 450-700 lopey and very rough due to the large cam

 

800 - 900 makes more sense.. trying to make it idle at 450 -550 and the oil pressure drop to just about nothing.. ( about 15 - 20 psi ) and keeping it running is almost impossable.. Is there a way to check the IAC unit if its working? the books only says how to remove and replace.. but not how to check.. I did find out that my ECM does not check to see if the IAC is working...

 

thats what mine runs.

 

well 550 is what mine runs. WTF? how did that happen? 2 at once?

 

pull the iac and see if theres any dirt or anything built up in it
15-20 psi at idle warm is ok check that ur tps is adjusted right also that can mess up ur idle also