Turbo boost sensor

[Brickster]

Hi guys. First post. Having erratic throttle response. It is most pronounced when it is cold but what is happening is that when I accelerate while driving, it will race up to 2500 rpms then back down to 1400. This cycle will continue to occur all the way 30 minutes to work. I am a decent mechanic but had to take it in to have it scanned after I couldn't figure it out. Threw code p0238. I replaced the turbo boost sensor but it is still occurring. Any ideas?

[arveetek]

Sounds like a PMD/FSD issue to me. I've experienced erratic RPM control a few times, and it was always a PMD/FSD problem. If you've replaced that and it still acts up, probably an internal Injection Pump failure.

Does it happen when using cruise control? If not, it could also be the Accelerator Pedal, but I doubt it.

Casey

[Brickster]

Thanks for the reply. I believed the pmd failure would not have those symptoms. Just a no run condition. I wont rule it out though... It does have the same issues with cruise control on. Pedal checked out ok. Maybe a short in the wiring from the tbs to the pcm? The wiring gets lost in the harness bundle and hard to trace. Anyone know how to test the wiring?

[arveetek]

Definitely try the PMD first. Will probably save you a lot of headache.

When mine has failed, it wouldn't hold a steady RPM, even on cruise control.

The PMD failing typically results in a stall or no start condition, but can also fail to full throttle scenarios... which is quite scary. Unsteady RPM is also another symptom.

Casey

[Brickster]

Okay you talked me into it! I suppose for whatever reason it wasn't the fix I'd still have a spare. Thanks.

[Brickster]

Nope! The PMD was not it. :mad: Now I am thinking It may be the wiring between the sensor and the ecm. Thoughts anybody?

[Artworks]

Check all vacumn hoses attached to sensors and turbo.