Idle Issues

[itwonder]

Have you had the intake off to verify its gaskets are okay? Could be a vacuum leak at the master cylinder to booster gasket, but you can usually hear those. Fortunately, there are not that many vacuum lines on the SHO intake. OTC 4506 pinch off clamps are handy to block them off. If the IAC is good; how about the IAC passages in the intake - are they clear?

 

[Black91SHO]

If it were the intake manifold gaskets, it would be a persistent problem rather than random. It's the MAF. That fixed the problem. Runs smooth now.

Thanks for all the help, guys!

 

[itwonder]

Congrats on finding the problem Brian!

 

[rubydist]

good for you - did you replace it or just clean it?

 

[Black91SHO]

I swapped it with a used one.

 

[DeepPower]

Any trusted brands anyone can recommend if I want to buy a brand new MAF? Delphi, Cardone, Dorman, Hitachi?

Ford p/ns for an '89 SHO MAF:
E9Zf-12B579-AA
AFH55-03

 

[DeepPower]

Just cleaned my MAF with CRC MAF cleaner. Much smoother idle now.

 

[Black91SHO]

Great! That's a much cheaper solution.