Four problems related to engine have been reported for the 2003 Ford Ranger. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Ford Ranger based on all problems reported for the 2003 Ranger.
Truck bucks/jerks during drive cycle when in 3rd or 4th gear, rpm ~2500.
A failed roller rocker destroyed a cam and lifter after only 66,000 miles. 3,000 miles previous I had taken it to the dealer who said they couldn't hear the noise. By the time they could hear it, the damage had more than tripled. The failure was definitely caused by the defective roller rocker(the part is available for inspection).
When the transmission is engaged, automatic, on acceleration, there is a chattering noise coming from the engine area. Happens whether a/c is on or not.
When placing vehicle in reverse, motor raced with foot on the brakes. It was later determined by dealership that it was a computer problem and was reprogrammed. This remedied the problem temporally. Failure has occurred numerous times since the part replacement. Consumer felt if Ford couldn't repair the vehicle without it failing again, then his money should be returned.