kingman109

okay - putting cats back on to go through emmisions and cleared my O2 codes.. everythign is great for about 5 days. no SES light nothing- drove about 400 miles.

then day i decide to take her through my SES light comes on.. So i scan it and come up with P0400 (Exhaust Gas Recirculation Flow Malfunction ). so i assume its EGR and buy a replacement- today i swapped it out and tested the old one.. it was sticking when the baffle was closing...great problem solved... well i decide to hook a vacum up to the egr and make sure car stalls to make sure everything is working...idle doesnt even budge..

so i test my vacum lines and they are all perfect...solonoid is operating correctly but when i hook my vacum up to the egr it just pulls it. i took the EGR off assuming there is blockage into the manifold...scrape it out and spray some carb cleaner to be sure...rehook everything up and same problem... i dont get it... what could be wrong?

i cleared the code for now and will drive around to see if it comes back up but im curious what could be wrong? any ideas?

fredmr39

I'm having similar problems - from what I've learned from Ion, some cars will throw EGR codes after headers even if all is operating well. For me, I was clear of codes for a while until I used 6th gear....THEN SES came on...

kingman109

yes... but its not just throwing a code...

the car should stall or at least change idle whenc vacum is applied to the EGR... which it is not. That means something is not functioning correctly...

fredmr39

interesting - any updates?

kingman109

well - appears to be functioning- put about 350 miles on her and no codes - i go through emmisions on tue so hopefully she holds..

i and my mechanic friend just cant figure out why she doesnt stall under vacumn

Dave89IROC

these EGR valves need some backpressure to open, not just vac