Rough Idle SES-Lite on- OBD1, No Codes Found

[xsmilk]

sorry for the non item... I am unable to access the Trans sport forum? " heavy site traffic"" ??? I accessed this thread from the pontiac general thread.... is this a wide spread issue??

[LMP]

Originally Posted by xsmilk

sorry for the non item... I am unable to access the Trans sport forum? " heavy site traffic"" ??? I accessed this thread from the pontiac general thread.... is this a wide spread issue??

Yes it has been like that from Saturday...

[rockwood84]

if the egr valve is easy to pull off then you can clean it with a can of carb cleaner push the plunger back and spray the seat real good. an egr valve uses a plunger and seat to control the cycles . they get gunked up and the plunger can't seat. on my 3.4 it is **** to get to . good luck

[Benesesso]

OK, I'll try to clean it.

[rockwood84]

be sure to get the plunger to seat where no cleaner will pass thru it when it is closed. and i always put antisieze on the bolts when i put them back in. also have you cleaned the iac valve as when they get clogged they tend to mess things up too. good luck

[Benesesso]

The van was running well with the blocked-off EGR valve, so I just drove it with the SES lite on. Today it started running like crap again, bad stumbling at part throttle, but fine under a lot of throttle.

I figured my homemade blocking gasket had burned thru, so I zipped off the 2 hold-down nuts and lifted the valve off. Surprise, the gasket looked fine-not even heat-discolored. Then I looked into the valve and saw some kind of broken ceramic nozzle or restrictor. One piece of it had fallen out when I lifted the valve. The rest of it was jammed in the valve, so I pried it out with a small screwdriver. As soon as I did I saw a steel-? piston that was behind it. The piston/valve? moved down under a light spring force as soon as the ceramic was removed. I could easily push the piston back up the valve, and the spring would then re-close it.

Put the valve back on-with the block-off gasket-, and now the van runs fine AND the SES lite if off! I have to believe the computer was able to sense that the valve was stuck open-?, and must have cut the fuel being injected way down. The was no way any exhaust gas could have gotten past the blockoff gasket.

BTW, there is a short metal flex pipe right next to the EGR valve, but it doesn't connect to it.

[rockwood84]

that is the egr piston that lets the egr cycle it was probably bad when the light first came on .as the piston opens on one /closes on the other and it has to seal .