erratic miss

[Ray Kendrick]

My 87 GN has developed an erratic miss. Seems to have occured after a major tuneup involving new module, coil pack, plugs and wires. It failed the Harris county emissions test. Had it to 2 places that "specialize" in GN's and no luck. They tried another computer, different chips. It's had a cold hesitation for a good while, but that hasn't changed. Any ideas?

 

[Brian Mc]

Good luck, having same problem with no luck.

 

[GNFURY]

well, I gues did you check all dumb stuff? Check and see that you followed the firing order correctly when you put the new plugs in. Check your gap on the spark plugs. And visually inspect the spark plugs. If they are the kind that you splice to the correct size, check and see if the splices are done correctly. I have a friend with this problem, and the guy that did the wires had **** contact on 2 out of the 8 wires he put on the car, causing a crappy miss. Also, if you got the coil pack replaced, have it tested and make sure that it is good. Did you set the cam sensor, or adjust it during the tune up? If so, double check it's setting too. After that check up, at least you will know that if you have to spend money, it's gonna be on something worth it. Nothing worse than getting a $300 repair bill, plus finding out that after they replaced your ________ that it turned out to be a bad $5.00 plug wire!

hope this helps

 

[V8 KILR]

just a thought....

I failed emissions once because of a bad coilpack. It was brand new, but it was faulty. Replaced it with an AC Delco coilpack and sailed right through the test.

Since the misfire seems to have appeared after the tune up, suspect something that was changed. If you still have them, you could reinstall your old parts one-by-one (as long as they were performing satisfactorily) and see if you nail it down. Good luck.