Recently i picked up an 85 Berlinetta with a 2.8L / 5 speed in it. When i got it it sounded like it was running on 5 cyc and would not stay running. After finding the problem, i replaced the #3 cyc exhaust spring and as i was sealing it back up, i treated it to some new plugs, wires, cap & rotor button. now it runs but very idles really low. when i step on the gas, there is a hesitation and then it revs up. Thinking it was the timing, i checked it with the advance disconnected and it's spot on. After looking at some of the other posts it appears it could be anything and that i should start by looking into the different sensors (MAF TPS etc). Rather than throwing money into new sensors and hoping one of them fixes my issue i would like to actually check the voltages and pinpoint it. can anyone tell me what voltages i should expect at the different sensors? Thanks....Rob

 

I would clean the MAF and the TB. Make sure that there aren't any leaks between the MAF and the TB, as that will be un-metered air. TPS could be dirty or worn. Also check the fuel pressure.

See attached for voltages at ECM.

RBob.

 

Thanks, that's a big help. The other day while checking the timing, i had the car warm and running. i set the timing light on the flex tube between the air cleaner housing and the TB and the flex hose came loose. (i had forgotten to tighten the clamps) i took it off to reposition it as the car was running and it stumbled and almost died. Is that normal? In the past i had a 92 RS with a 3.1L that didn't care if i removed the flex tube but this 2.8L seems to be more finicky.

 

Yes, normal. Has to do with the MAF and the airflow through it.

RBob.