CEL light is back on and spitting and sputtering again! Replaced distrib and rotor last time(August '09) and it took care of the problem(not injectors). Does anyone know if something could be killing the distributor cap and rotor? Replaced with AC Delco parts so shouldn't be bad yet. Plugs are AC Delco and replaced last time when this happened so wouldn't think it would be those either. How do you tell if a plug is fouled? FYI: seems to be worse when running steady.

It also sounds like I have an exhaust leak under the hood. Could this have something to do with it?

Thanks,

 

Tim,
I had this problem about 1 1/2 years ago (and previously) (and it came back about 2 weeks ago. The last 2 times this has happened to me it was the EGR valve sticking (or stuck).
I plan on replacing mine in the next week.
My engine light comes on when excelerating (mostly on the highway over 60 mph).
If I stay in town, the light doesn't come on at all (after resetting).
I have dual exhaust with no muffler, its just right out of the cats. This apparently makes the EGR valve fail quicker according to a few mechnics I have spoken to about this issue.
Also the more oil your engine burns, the quicker the EGR valve will fail.
EGR valve is about $190 at Napa.
Keep me posted on how you fair on this.
Thanks,
Jim

 

Thanks HDMAC! I'll see if that does the trick, but my check engine light stays on constant. Took it to the mechanic this weekend and it showed the P0402 Cat Conv. code along with P0300, so I had the cat replaced hoping to eliminate all problems with the replacement. Didn't solve the miss fire! I really don't like replace good parts if I don't have too and the EGR valve isn't really cheap. Is there any way to check if it is bad/going bad? Like I said I changed the distributor cap and rotor and think that the plugs and wires are okay, so is this my next option?

Thanks,

 

The EGR valve works by routing a small amount of exhaust back into the combustion chamber. When the temperature in the combustion chamber is too high, nitrogen oxides are produced, which combine with elements in the atmosphere to form smog. Introducing a small amount of exhaust into the system reduces the temperature in the combustion chamber, reducing the amount of nitrogen oxides produced.
Many EGR valves are mechanical, and simply have a small valve which opens to allow exhaust into the combustion chamber and closes when it is not necessary, and to keep the air mixture optimal for combustion. Some mechanical versions will not open until there is sufficient back pressure, ensuring that the valve will not be open when the engine is idle or warming up and needs a higher concentration of oxygen for combustion. Electronic EGR valves are also available, and use electronics to regulate the valve.
If the EGR valve is stuck open, it will essentially cause a vacuum leak, leading to inefficient combustion, rough idling, hesitation, and sometimes stalling in extreme cases. This is because the car cannot combust on carbon dioxide from the tailpipe — it needs atmospheric oxygen. If the combustion chamber is flooded with exhaust from an open EGR valve, it will not function properly. To check and see if the EGR valve is stuck open, have someone idle a parked vehicle with the brake on while you examine the plunger shaft to see if it is stuck open.
If the EGR valve is stuck closed, emissions of nitrogen oxides will rise, and the car may start to knock. Spark knock happens when the fuel mixture in the combustion chamber ignites before it has been reached by the explosion in the cylinder, resulting in a disruption of the engine timing. In this instance, the engine should be warmed up and revved to see if the EGR valve will move.
In both cases, simple repairs are possible. The EGR valve can be clogged, and a simple cleaning of a mechanical EGR valve may solve the problem. In the case of an electrically controlled EGR valve or a more complex mechanical problem, replacement of the valve may be needed. The EGR valve is an expensive motor vehicle component, and care should be taken to ensure that it needs to be replaced rather than repaired. A reputable mechanic should advise you appropriately.
Hope this helps. Take it off the vehicle if you cannot tell on and examine the unit - does it move? Is it plugged as so it cannot move. I have luck and not so good luck cleanning them. But for $200, I would try cleanning it first.
Jim

 

I did not read all so i dont know he said it but try to clean the egr valve before replaceing it

 

Thanks HDMAC & 992door! I'll try cleaning the Egr valve and see if that will correct the problem. I did go ahead and replace the spark plug wires and distributor cap/rotor as I got advised by a mechanic to do so. Hopefully cleaning the EGR valve will remedy my problem and I will post what happens. Thanks again for the posts.