No Power at low RPM's

[Paul Foster]

I have an 03' with 113K on it and it has no power at low rpm's. It has new injectors in it. No codes at all, it won't build boost until 2500 or more and then it runs great until you let off the throttle. It has new downpipe back exhaust and a cold air kit on it as well as a new fuel filter. No smoke under load either... any ideas?

[DmaxMaverick]

Filters. Air and fuel. If you haven't changed them since this problem began, change them before looking for any else. This is also what the dealer will do. Also check the PCM for stored codes. If the SES is on, you probably have a MAF related code (could be caused by a wet-type air filter, clean the MAF also). If no help, reinstall your OEM intake and test again. Some of the aftermarket kits don't quite have the MAF position correct, causing erroneous intake air readings, preventing proper fueling at low RPM's. If the problem still exists, it needs to go back to the dealer (with the OEM intake installed). Don't reinstall your OEM exhaust, and don't let them tell you the exhaust is the cause. It isn't, even if you have a CA emission model with EGR/CAT.

That said, turbo spooling will be delayed somewhat during hot weather, compared to cold. But, only a few hundred RPM's at the extreme, not clear up to 2500.

[Mark Rinker]

Welcome aboard!

Not a typical scenario - sounds like lack of proper fueling if no smoke assoicated with low power. Weak pump? Restricted fuel flow?

I'd get it on a scan tool and check FRP stats, first. If they are normal, then would be looking for turbo issues...although there should be black smoke with normal fueling and low boost...

Hmmm...

[Paul Foster]

The filters are new and the aftermarket intake and exhaust were added after this problem started. One other thing, it is much worse when cold, it will act a little better with the engine at operating temp. What should the fuel pressures be? I can see the actual follws the desired pretty close. Thanks for the help