Rough idle has returned. 2 years ago I had engine harness replaced and one new coil, new plug wires and boots to plugs. 6 months ago I also had the alternator rebuilt.
I pulled the following basic codes: 2,5,6. I also tried for detailed codes on two pins and got on pin 8: code 1 (no code) and pin 14: code 3. Should I try any other pins for more detailed codes?
Another coil is probably bad (15.9 kohms instead of 6.5 and 6.6) and I am ordering two new coils, just in case the third one fails (plus new spark plugs). I assume the boots should be still good (2 years, 25k miles)?
Among the threads I searched I found the following one by eorossi; it has good info on the egr cleanout.
http://www.peachparts.com/shopforum/showthread.php?threadid=68452
I will try to clean the egr opening to the manifold. There is a 1/2 inch x 5 inch flat steel plate in the way; it is part of the throttle linkage; can I pop it off to improve access? Speedo cable has been mentioned to clean out the egr pipe; can I pick up any cable from my local Carquest or NAPA or does it need to be a certain type for flexibility.
Last, where is the egr valve located? Also, I'll check to see condition of the vacuum line under the engine. Other vacuum lines seem ok (but they are rather hard to find and follow).
Any other ideas? Thanks!