1988 ranger slight rough idle

[86ranger4x4owner]

I have a 88 ranger 2.9l and at idle it has like a slight miss kind of or rough idle its not bad but its noticeable. Could the IAC cause this?I did clean it a few months ago because it was surging at idle. coud it also cause a slight rough idle? also the rough idle goes away after you rev it past 1500 and happens in gear or park

 

[CajunPwnStar]

Could be a few things.

Test your fuel pressure first. Should be 30-40psi with the engine running / 35-45 Key on, engine off.

Test for a vac leak, if you have something like a Mityvac hand pump and gauge. If not, you can use cigar smoke to check for a vacuum leak. Take a huge drag(don't inhale) and blow it along vacuum lines. You should be able to see it suck it up. Could also be the EGR valve itself.

Another possibility is the fuel pressure regulator.

I'm assuming the fuel filter, plugs, and plug wires are in order?

 

[86ranger4x4owner]

Could be a few things.

Test your fuel pressure first. Should be 30-40psi with the engine running / 35-45 Key on, engine off.

Test for a vac leak, if you have something like a Mityvac hand pump and gauge. If not, you can use cigar smoke to check for a vacuum leak. Take a huge drag(don't inhale) and blow it along vacuum lines. You should be able to see it suck it up. Could also be the EGR valve itself.

Another possibility is the fuel pressure regulator.

I'm assuming the fuel filter, plugs, and plug wires are in order?

fuel pressure is good. no vacuum leaks checked all vacuum hoses and has no high idle. I took vacuum line off of the fuel pressure regulator and so signs of leakage and the fuel filter plugs and plugs wires are actually new