Engine won't rev over 2500 rpm. Help!

[jjuanwil]

While sitting in Park, my 05 Expy will rev fine up to 2500 rpm, but then it won't go past that no matter how much you push the accelerator pedal. On the freeway I can run it at 3000 rpm or more; don't know how much more without speeding.

I used a scanner on "live data" and found that the TPS reading will stop when you reach the 2500 rpm level, and then won't show any more advance when further pressing the accelerator pedal.

When the engine is not running, the TPS reading will go smoothly for the entire pedal travel.

Summary: TPS reading stops about half way through pedal travel when the engine is running; TPS reading continues throughout pedal travel when the engine is not running.

I have replaced both the TPS and the Throttle body with accelerator sensor.

What could possibly cause this to happen?

 

[toms89]

If I am understanding your post correctly you are saying your expy will not rev past 2500 in park/neutral but revs ok while in drive.

I don't know the specifics of your 05 expy but most software has rpm limiter for both neutral/park and drive independent of each other. Most times it much lower in neutral/park because there is no reason to have it rev higher. Due to the throttle by wire nature of the 05 your tps sensor readings may be governed by the software.

 

[Stoned06]

Second gens have a rev limiter while in park like Tom said.

 

[mc0311grunt]

Limiter. There should be no need to rev in park or neutral anyways. Believe it or not that can hurt the motor

 

[jjuanwil]

Thanks

Thanks,

I suspected something like a rev control, but had never heard of it.

 

[alaskanexpy]

yep, limiter.