Originally Posted by no_common_sense
I always wondered if the EGR valve, or the lack of, tied to whether or not the engine is flex fuel. The reason I wonder is because some engines do have EGR while others don't even in the same model years. I've had a thousand chances to ask smart people about that myself but i keep forgetting. I've got a head that's like pouring water through a collander. It'll retain something for a little while but it's always going to wind up empty again.
Haha, i know what you mean, completely forget about something you had in mind when you need it :P
I believe the EGR has no longterm benefit in an engine and is used to control emissions, maybe the location where my van was built doesn't have strict policies with emissions. Furthermore, I find the EGRs on the 3.8s not the 3.3s.
Regarding the problem at hand...
- I cleaned the throttle plate and got rid of LOTS of black gunk, just kept pouring.
- I seafoamed the van, however i was a bit cocky and didn't let it sit in the engine for more than 5 minutes... I think i will have to do it again.
- Did a compression test and got the following readings (in PSI):
I would like to note that the compression tester i bought was $20 with 2 adapters, definitely low quality :P
- Changed plugs (Iridium IX) and Wires (AutoLite Professional)
Guess what... That Rough idle is still there!!!
Now i am thinking it is not the engine, because its only in D, R, 3 and L that this really rough idle occurs at 700RPM, Just a bit of throttle to get it above 1000 RPM it shuts up and is smooth.
Last thing that i may try cleaning is the oxygen sensor, after that, i am stumped...
I was wondering if the power steering pulley could be causing this, because when i turn the wheel, the rough idle becomes more aggressive?