Dwolniak

I have a 1995 se and I randomly have been getting this damn p0400 code. The car is at 140k and i cleaned the egr tube out at about 125k and i just recently checked it and wasnt clogged up. Also put a vacumm pump on the egr and the car started to stall out when applying vaccumm.

I checked the Egr solenoid, but everything looked fine on it, I took it apart and cleaned it.

Would it just be worth it to just replace it?

Ive searched around and it seems like no one has a sure answer on this problem.

Dcarlton

I have 2 Max's, a 95 and a 97, have never ever received the P0400 on the 95 and couldn't get it to go away on the 97. The 95 never got the code even though the EGR tube was completely clogged.

The 97 has been on so much the SES light burned out.

Here's what I have done and I may have fixed it on the 97.

I replaced the EGR valve - stayed off for a couple of weeks, but did return.

Cleaned EGR tube, intake manifold, IACV, throttle body, you name it, it was cleaned. - code returned in a couple of weeks.

Swapped EGR temp sensor from 95 to 97 - code returned after a couple of weeks.

Did replace knock sensor on both cars - was melted on one, cracked on the other - the Knock sensor code went away but the P0400 returned.

Kept digging, kept reading. Some suggested bypassing the BPT to see if the BPT was causing it. I haven't done this but the BPT was replaced 3 or so years ago when daughter bought the car.

EGR solenoid seems to be okay, could replace it with one from 95 but haven't done so - did replace it on 95 when the code for it came up.

Read some more and discovered via Google that a few indicated the gas cap may be faulty or not have been tightened enough at fill up. Considering the randomness of this P0400, didn't seem to be triggered by city or highway driving all the time, I figured I could replace the gas cap. I had noticed that for some reason, the gas cap on the 97 was a Fram one indicating it had been replaced before.

Bought a new gas cap for about $9 around Dec 1, 2012. Have driven a mix of highway and city, filled up, or added gas several times and so far, the P0400 has yet to return.

Some indicated that a gas cap check (pressure maybe?) was part of the EGR system check. I don't know if this is true or not and can only say time will tell if this has corrected my issue.

Like you, I had tried everything else and figured this < $10 fix couldn't hurt and if it helped, I would be happy.