Got my car scanned and pulled a PO400 code, egr malfunction. After reading the posts relevant to my problem, i sprayed some cleaner on the egr valve, got it to flow smoothly, and then tested it with the engine running (when i pushed the diaphragm, it stumbled). Then, i reset the PCM to get the SES to go off. I drove it around town and then took it on the freeway. as soon as i got to about 65, the light came back on (assuming the same PO400 code came up). I then read some more and found that the culprit may be lack of backpressure. I have a borla catback with the 3" open plate in it. Could this be the problem? If i put the closed or small plate on, assuming that is the problem, will the SES light go off, or do i need to reset the PCM? I'd like to know soon, because i'm trying to sell the car, and am going to take it to the dealer to get diagnosed if neither of these things solves it, which i dont really want to do. Thanks.

 

i have the borla catback and never had the egr problem untill i removed my catalytic converters and put headers on. now everytime i am in 6th gear going about 60mph for longer than 5 or so minutes the ses light comes on. i went ahead and just bought a new egr (still get the faulty egr code) so i know my problem is caused by the lack of back pressure.

if you still have your catalytic converts on you should be ok with the back pressure, i would say you might just need to invest in a new egr valve.


edit: i ran my car with the borla open plate and stock manifolds w/cats for over a year with no egr code. my car is also a 96.

 

had the code before and after headers. sets off at highway speeds. started on test ride from dealer. fixing was condition of sale. went off and under warranty they replaced egr valve, solenod and vacuum lines. still threw code. diagnosis was non OEM exhaust. offered to put OEM set up on it. I told them to forget about it.

contacted borla and their reply was there were no known conditions with their system.

seems to be a backpressure issue at 55 mph plus in 5th or 6th only.

some have tried the medium size plate with some success. i just left it wide open. close off plate might work too.