bad miss, any suggestions

[mconn116]

Hey yall got a 97 ranger with the 4.0, it has a bad miss the code says its on cylinder 4, ive changed plugs, wires, coil, fuel filter, I did a compressions test and got 145 lbs but when a shope did it they got 60???? Ive had suggestions of it being the fuel pressure regulater, clogged cats, camshaft position sensor, any suggestions or anyone else think it could be one of those?

 

[Big Jim M]

Sounds like a burnt valve doesn't it? Do the compression check again. This time take out all the plugs and hold the throttle wide open while testing.
A bad miss on a single sylinder is usually a spark plug or a valve. You seem to have the spark plug covered.
Valves burn from a LEAN mixture in that cylinder. LEAN mixtures can occur from an air leak into that one cylinder. Look for either an intake leak or an exhaust manifold leak near that cylinder for a source of extra air intering that cylinder.
Big JIm

 

[BRUTUS_T_HOG]

Hey yall got a 97 ranger with the 4.0, it has a bad miss the code says its on cylinder 4, ive changed plugs, wires, coil, fuel filter, I did a compressions test and got 145 lbs but when a shope did it they got 60???? Ive had suggestions of it being the fuel pressure regulater, clogged cats, camshaft position sensor, any suggestions or anyone else think it could be one of those?

you didn't change out the fuel injector yet. try swapping the fuel injector for another cylinder and see if it changes to the other cylinder.

i would do the compression test again too