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I have an 07 Foerster 2.5 non turbo that threw a p0402 code…

I have an 07 Foerster...
I have an 07 Foerster 2.5 non turbo that threw a p0402 code about 3 weeks ago. Been driving fine until the other day on the highway, I went to accelerate to pass and the engine bogged down. It smells like it's running rich.
It runs fine idling, even when I put it in drive foot on the brake and rev it up it holds rpm and runs fine. The minute I take it down the road and try to accelerate it bogs down has a deep growl (Like an after market highflow intake sound) and I can not give it more than 1/4 throttle. Anything more than 1/4 it starts to big.
I have checked all fluids
Changed 02 sensors up/down stream
Changed Cat (full front exhaust)
Changed plugs, wires, coil pack, and maf.
I'm stuck?
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Answered in 1 hour by:
11/19/2017
Matt
Matt, Engineer
Category: Subaru
Satisfied Customers: 22,618
Experience: Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
Verified

Hello

to get that code then its pointing to excessive EGR flow, which would also explain the loss of power

there are several possible reasons

the last is the most likely so I'd suggest to pull the EGR valve off and clean it out

  • The EGR valve is opening all the way or more than needed due to a blocked vacuum diaphragm in the EGR vacuum back pressure valve.

  • The EGR temperature sensor is registering too much of a temperature change when the EGR valve is opened from a partly blocked exhaust catalyst causing excessive back pressure in the EGR system.

  • The EGR is stuck open due to binding or carbon deposits holding the valve open.

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Customer reply replied 2 months ago
Sorry for the delayed response work has been very busy. I just put a new egr valve on still have the same problem.

Hello

OK in that case I'd say to try fitting a thin blanking plate between the EGR valve and the inlet manifold with a tiny 3mm hole in the middle so there's a fraction of the EGR flow if this then helps and the valve is free moving then you know the issue is an electrical one so checking over the EGR valve wiring loom and connector would be the next step. or you may choose to just leave the blanking plate in there of course

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Hi
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Thanks Matt

Matt
Matt, Engineer
Category: Subaru
Satisfied Customers: 22,618
Experience: Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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