2000 Ford Ranger runs rough

CHRISCURREN

MEMBER
2000 FORD RANGER
6 CYL
2WD
MANUAL
171,000 MILES

Hi, at first the engine acted like there was a governor on it when more power was needed. It would just mis fire. I changed plugs and plug wires, new air and fuel filters. New pcv valve and one of the oxaygen senors (after cat convter). I've check all fuses and checked ingintion for a strong spark. Most cylinders ran about 145-150 with a compression test except #6 which was 125. I've also run plenty of injector cleaner through fuel system. Now what?

1 Reply

RACEFAN966

MECHANIC
5,029 POSTS

Ok do you have a digital multi meter? You will need one if not. I would like you to test the TPS to see what it is doing. Use a paper clip and back probe the gray wire with the white strip at the TPS (throttle possition sensor) and set it on the 20 volt scale and then turn the key on with engine off. Now you should read around.8 volts now slowly lift the the throttle it should slowly increase in voltage with no drops or glitches. Now at full open throttle it should read 4.5 to 5 volts. If you find the voltage drops or there are any glitches as you lift the throttle then replace the tps. Now the other thing I need you to check the Mass Air Flow Meter. If it runs rough at idle to then unplug it and see if it idles good. If it helps with idle quality then get some mass air flow cleaner (no other cleaner) and pull the mass air flow meter and clean it, just spray the inside of it with the cleaner it won't take a lot and reinstall it and see how it runs. Let me know how this goes as we will test the mass air flow meter next.