Ranger will not idle right, tried everything.

[Lonesome7.3]

87 Ranger with a 2.9
I have tried everything I can think of the track down the idle issue with this truck. It ran like crap when I got it and it runs over 100 times better now. I have replaced the TPS, idle air valve, modulator, plugs, wires, cap, rotor, timed it, replaced vacuum lines, pulled and cleaned the air plenum, deleted the cats, and repaired numerous wiring issues. I sprayed two cans of brake cleaner all around the engine compartment and no vacuum leak was found. I have run a lot of fuel system cleaner through the tank and replaced the fuel filter. However, I have not yet hooked a pressurized fuel system cleaner to the fuel rail yet. I know that really should be done. It idles high sometimes, and when it is not doing that it idles rough. The other issue is it stumbles going uphill. What am I missing? I think it is a fuel issue.

 

[That Crazy Squirrel]

Easy enough to see if it's a fuel issue (or fuel/air issue)... Take a propane torch, UNlit, and feed it a bit of propane while it's idling rough. If that "fixes" it, you're running lean. If it dies or gets worse, you're rich.

You could also do this while driving, just use some hose to reach the intake (and allow time for the gas to flow through)

 

[Alljackedup408]

Need to see fuel pressure no doubt.

 

[That Crazy Squirrel]

Oh, and to me it sounds electrical, and those are known for "eating" coil packs, but check mixture first anyway.

 

[Lonesome7.3]

I never heard of the propane trick. Will MAP gas do the same? I need a new fuel pressure gauge.

 

[Lonesome7.3]

Did not think of the coil.

 

[That Crazy Squirrel]

I never heard of the propane trick. Will MAP gas do the same? I need a new fuel pressure gauge.

Yep, MAP will work.

 

[Lonesome7.3]

have some of that.