Hi. J.T. here. My ranger is a 94 SuperCab 4.0 auto with 199,000K. I have a bad ping when under load or heavy acceleration. I've tried high octane gas, octane boosters, fuel system & injector cleaners. New plugs & wires. Cleaned MAF. New Fram Air Hog air filter. Nothing seems to help. Am desperate for some answers! Any input would be greatly appreciated.
Thanks,
J. Terry

 

First try some Seafoam through the brake booster line to the intake.With that many miles there are probably carbon deposits in the combustion chamber creating hot spots.
After that I would consider changing the O2 sensors as they may be old and out of spec telling the PCM the engine is running richer than it actually is.
Next on the list would be the Throttle Position sensor.Test and/or replace it.
Check the fuel pressure at the fuel rail.Should be around 60 psi I believe.Changed the fuel filter recently?

 

Hey guys, I'm new here and I just got a free 92 4.0 ext cab that runs good but has the same ping under load... What is seafoam? thanx Wll.

 

Seafoam is a just a brand name, but their products are excellant! Tranny additives, motor additives, fuel adds., etc...
J. Terry

 

Thanks To All, The SeaFoam thru the brake booster vacum line worked great.

 

Thanks for reporting back. As I was reading down through your description I was thinking it was combustion chamber carbon buildup. With that many miles on a motor, its usually the root cause.

What I usually do to all my cars: twice a year I run two cans of chevron w/techron FI cleaner in a single tank of shell 93 (v-power)
I've done that for years and have never had a problem. And the engines I've torn down all are very clean. Only once did I see a little coking on some valve stems. But it still wasn't enough to cause problems and was very minimal at high mileage.

btw, FI cleaners are not all the same. The "techron" cleaner is good stuff in my experiences of using and rebuilding my own engines.

Rich