Hello everyone.

I have 96:Ranger 4x4 4.0l manual that I have a real problem with. At highway speeds of say 70+ and in fourth and 5th gear the truck will miss. This happens totally randomly and you never know when it’s coming. It does seem to happen noticeably when you hit a good bump a few seconds later but otherwise totally random and unexpectedly.

Some details. No CEL. Scan of the vehicle stated TPS and O2 sensor. TPS has been replaced, no change. O2sensor has not. MAF has been cleaned properly, no change. It has been getting steadily worse missing more and more frequently. Truck starts and idles perfectly. Around town and in stop and go no issues.

If anyone has any ideas please let me know and thank you to anyone who responds.

 

Welcome to the forum

Pull the spark plugs and check the gaps, 4.0l likes a wide gap, 0.054 is spec

Also clean the tips and compare all the spark plug tips to see condition inside each cylinder, tells you if injector is leaking or valve guide seal is leaking
Never use single platinum spark plugs, waste of $$ in distributorless vehicles
Double platinum or regular copper only
Just a heads up

Also spark plug wires last about 15 years, well 10-12 years really because they will cause misfires after that, you for sure notice they are bad at 15 years old

Can of Seafoam in the gas tank once a year helps keep injectors clean

New fuel filter every 5 years