1992 Ford Ranger

Have 1992 Ford Ranger 4cyl with two plugs per cyl. recent tune up, plugs, wires, air, fuel, and oil filter. Problem...It bucks once it warms up. No "Check Engine" light. Light does work, as it comes on for the bulb test before you start truck. The longer it runs, the worse it runs. Fuel pressure is at around 42lbs with fuel pressure gauge attached to "T" in fuel rail. It has "spark knock" really bad when trying to accelerate., really had to start when cold. Was told it could be the cam shaft is worn out. Truck has over 122,000 miles on it. Any input would be greatly appreciated. Should add, that after the truck has been started once, it starts fine for the rest of the day no matter how long it sits. It just is a real pita to start after it's sat over night.

Cory

 

Tests/Procedures:

1. The engine starts and runs on the exhaust side coil. The intake side ignition system is turned on and off as needed. Make sure that the plugs and wires were installed correctly on the exhaust side ignition system. The firing order is printed right on the top of the coil.

Potential Causes: Wrong or bad plugs
Incorrect firing order

 

Rangers are very picky about the plugs they use. I had a 96 Ranger and it would only take OEM plugs. I had the same problems as you and it was fixed by using OEM plugs and wires.

 

i'll recheck the plugs and wires, i used the same brand of plug that was on there, autolites.

 

One thing I always check if my car runs bad is the air flow sensor. On my altima the sensor is "in charge" of the injector bursts. My sensor is by the air filter and I clean it with can of compressed air.