My 2002 4.0 v6 ford ranger will not rev past 3000 rpms while in park or drive. The check engine light is not on. I have considered the rev limiter but i'm not sold that is the culprit. I cant start it while in drive so the DTR is likely functioning.

I considered a clogged exhaust, but I pulled the upper O2 sensor and it did not improve.

Ive heard it could be the cam sensor, or maybe a bad fuel pump? I cant figure out how to test the fuel pressure because there is no schrader valve on the fuel rail.

Any input would be greatly appreciated

Thank you!

 

Welcome to the forum

The computer has a REV limiter set at 3,000rpm
In Park or Neutral engine should NOT be able to REV past 3,000rpms

In Drive that's a different story, unless speedometer is at 0, well, actually under 10MPH, then REV limiter is back
So is speedometer working?
If not thats your problem

Yes, clogged exhaust system or limited fuel flow will prevent higher RPMs, but 3,000rpms sounds to specific for that, reads like computer is doing it

Computer decides to use REV limiter using "neutral" switches or speedometer
If you have an automatic then it might be the DTR sensor on transmission, neutral switch
If manual trans then the Clutch neutral switch
These tell the computer WHEN to use the REV limiter

If automatic, and speedometer works, see if you can drive with engine above 3,000rpm in 2, if so then its the DTR most likely
Clutch switch is harder to test, need to use Volt/OHM Meter