Engine Revving for no reason....

[BrdHunter01]

I have a 99' ford ranger with 99,000 miles. If I'm going 55+ MPH my engine sometime (not all the time) revs an extra 500-700 RPM's for no reason. I took it to autozone to hook it up to there computer. The guy said it may be something with fuel. The computer said it could be a fuel pressure regulator (which was just replaced about a year ago), MAF (mass airflow censor)which is a $100 part, or a vacum leak somewhere.

Anyone have this happen before or want to suggest where I should start? Or any other ideas on what it might be?

Thanks

[BoxMN]

Had that happen to a 98 malibu recently. I think it was a Throttle Control Module (not sure about the word "module", but throttle control something - I think it might have been a word starting with "I" but can't recall...)

First they tried to clean it for me (for free, a buddy) but said if it happened again, I needed a new part. I ended up needing the new part. I think about $100 at a shop, then doing all the work. It was fairly common thing I guess. Good luck!

[Jeremy airjer W]

Sound like its not going into overdrive.

[BrdHunter01]

Sound like its not going into overdrive.

It goes into overdrive. But once in overdrive it rev's up like it is (or wants to) downshift....

[BoxMN]

Had that happen to a 98 malibu recently. I think it was a Throttle Control Module (not sure about the word "module", but throttle control something - I think it might have been a word starting with "I" but can't recall...)

First they tried to clean it for me (for free, a buddy) but said if it happened again, I needed a new part. I ended up needing the new part. I think about $100 at a shop, then doing all the work. It was fairly common thing I guess. Good luck!

Edit - mine actually would rev up and accelerate on its own. Like you were stepping on gas pedal, sort of like the old Audi issue, but with feet no where near the pedal. So seems like different than your issue after rereading.

[BrdHunter01]

Thanks for the responses.

[fishing tech]

Torque convertor lock up. When driving at 55 in OD tap the brake lightly and see if the same thing happens. If so the lock up for the convertor is going out. Mine lasted almost 50,000 mile before it finally died. That was 230,000 miles total.