Turbo RPM surge
 

I have been experiencing a surge in my RPM of about 500. When I let off the accelerator it drops back to normal and everything is fine. It is very sporadic. Some days it does it and some days it doesn't. I've had the truck in the shop for this and they replaced the seals in the fuel filter housing, replaced the fuel pump and the hoses going to and from the pump. Could it possibly be the waste gate? I have added a K&N air intake this past summer, but this problem started back in November of 2009. The truck has 233,000 miles.

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Bueller? Bueller?

EBPV ? Whats the temperature around you?

If you are getting an RPM surge without a corresponding surge in speed, What does that tell you?

You dont have a wastegate, so its not that...

Is the idle surging or what? I cant tell what your asking...

I do have a waste gate. Also, I'm not a mechanic. An rpm surge without power - would that be a transmission issue?

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Please tell me! I'm not a mechanic.

Please describe what is happening and when and under what conditions. We want to help,but need more information. Is it a stock automatic?

What you think is a wastegate is actually an ebpv (exhaust back pressure valve). It closes during warm-up to help the truck warm up faster.

94.5 to 97 powerstrokes do NOT have a wastegate... Sorry they just do not. That is why they have a 1.15 exhaust housing.

Sounds to me like the tranny is slipping but its hard to say. Is it doing this when under way or when sitting still? Is it movement related or motor related?

Sorry about the waste gate. The mechanic told me it had one. I hope he knows what he's talking about. The surge happens when I'm driving down the road. It feels like the truck goes from being in gear to neutral during the surge and then goes back to normal.

Sounds like the TC is locking and unlocking. Does it do this at a set speed or RPM?

Sounds very much tranny related.

I've had another friend also say the torque converter, but today a mechanic friend said the torque converter shouldn't rev the rpm like that. He said it is engine related. He's leaning toward the waste gate in the turbo.

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It is also doing this at any speed. The first time it happened I was coming home from St. Louis, MO going about 65mph. I've also had it happen doing 55mph and 35mph. As soon as I let off the accelerator it goes back to normal.