1998 Ford Ranger engine barely runs at idle cycles when acc

chancebase · Posted at Fri Nov 06, 2009 5:55 am

Engine Performance problem
1998 Ford Ranger 4 cyl Two Wheel Drive Manual 60000 miles

Was running fine when I parked in garage. When I started two days later engine idled exteremly rough,extreme shaking, engine near stalling. When accelerator is depressed halfway down engine begins to stall then speeds up then stalls then speeds up. This cycling continues as long as accelerator in depressed. I changed gas filter. I also checked fuel pressure at injector rail and found pressure within specs when engine not running key on. When engine barely running at idle fuel pressure increased but still within specs. What do I need to check next?

racefan966 · Posted at Fri Nov 06, 2009 8:15 am

Have you checked the air filter to see if anything is in it like a mouse nest or anything? If this checks out ok then if you would unplug the Mass Aif Flow meter and start it and see if idles ok then. Get back to me with what you find.

chancebase · Posted at Fri Nov 06, 2009 10:40 am

Had already checked filter etc.
Uplugged mass air flow meter as you instructed.
Started Engine and idled and ran engine. Runs normally at idle and when accelerated. I take it the mass air flow meter needs replaced.

racefan966 · Posted at Sat Nov 07, 2009 6:46 am

Ok if unpluging the mass air flow sensor makes it run normal or better then yes it needs replaced or maybe just cleaned. You can try cleaning it with mass air flow cleaner first. Let me know how it goes.

chancebase · Posted at Sun Nov 08, 2009 6:32 am

I cleaned mass air flow sensor with approved cleaner. "Didn't do the trick." Replaced sensor, problem solved, engine running great. I want to thank you for sharing your time and knowledge it is greatly appreciated!
Thank you!!!

racefan966 · Posted at Tue Nov 10, 2009 7:53 am

Great glad to hear it is running as it should again. If there is anything else you need just ask.