Mechanics

PROBLEM AT LOW RPM'S

1986 Ford Ranger

Engine Performance problem
1986 Ford Ranger 4 cyl Two Wheel Drive Manual?21000 miles

My truck is having this problem about 50% of the time.
When I am driving my truck starts sputtering and cutting out (as if it's not getting enough fuel or air). If I smash the gas peddle 3/4 the way down the truck takes off just fine. When I let off to cruise (no longer accelerating) it starts coughing and cutting out again. It does this at every gear (5 speed).

I have replaced: Fuel pump (both of them), Fuel Filter(both of them), TPS(set it to the right voltage), spark plugs & wires, air filter, distributer cap, distributer button, coil. I checked the O2 sensor(on the intake manifold and in the air intake/filter housing).

Any thoughts?
Avatar
Mholtz
November 1, 2009.



Have you checked the crankshaft sensor? The Crankshaft Position (CKP) sensor, located on the front cover (near the crankshaft pulley) is used to determine crankshaft position and crankshaft rpm. If it is dirty out of position or worn, it can cause this type of problem. Also, have you checked for vacuum leaks? EGR? And I noticed you didn't list the mileage. If it is high, have you checked engine compression?