I have been troubleshooting this for about 5 weeks now. I have a pretty good miss. It isn't consistant as sometimes it won't idle, and sometimes it will miss till about 3,000-4,000 rpm's. I would kinda say it acts like a burnt plug wire. I know that isn't it. That is what it is acting like. Cylinders 5,6,7,8 are colder then the rest. When I spray water on them, it takes a few seconds to evaporate. The front 4 burn water off instantly. The #8 plug is the only plu that has a very small amout of oil on the rim of it, and the plug is a little wet (prob from gas).

So far this is what I have done to it. I have replaced the plugs and wires twice. The wires are routed over the valve covers, and are wires from Elitesparkplug.com. I have replaced the coil. I have replaced the Opti(got it from Dal). I bypassed my Crane Hi-6 ignition box. I have replaced my knock sensor. I had a loom of wires on the passenger side get burnt very badly on the header(o2 wires, a ground, and another couple wires). I repaired all damaged wires. I have did a compression check, and all cylinders are even within a few % of each other. Before the burnt wires were discovered, I had a knock sensor fault code 43, and one time only had codes for left & right o2 sensors lean. All of my injectors are within tolerance of voltage and resistance. I visually inspected all my injectors, and the spray patters are all the same, and they all look strong. My fuel pressure guage reads between 40-42. My last scan this afternoon using datamaster has my right BLM maxed out at 160, and my left BLM is at 150. So it appears the car is running way lean. Right now after I fixed the melted wires going to the pcm, I don't have any error codes from the pcm. I am going to call Dal tomorrow and order a couple new o2's. The dealer here in town wants 125.00 a piece for them. haha yeah right. Any help would be greatly appreciated!

Thank you:

ZMAN

 

zman....it's going to be your O2's, and you will want to go ahead and replace those plugs too....sometimes (translated=rarely) they can burn back clean....but I wouldnt count on it. Best to fix the whole problem and not half of it. You could disconnect your O2's and see if it solves the prob. (keeping the pcm in open loop). But I wouldnt drive much w/ it like that.

Billy D.

 

Don't think Dal's gona beat these prices on the same O2s that he sells just with a different name. They are all made by Standard Equipment.

http://store.getgmparts.com/index.html

 

I ordered mine from Dal this morning for change less than 43.00 a piece. MY dealer here in town wanted 123.00 for the left one and 125.00 for the right one. hehe. I might have been born in the day, but I wasn't born yesterday.

Z

I also saved over 300 dollars by ordering from Dal on my Opti.

 

Another possibility is some issues with the injectors.

 

I have a friend mailing me 8 injectors that have 55k on them. I took a volt meter and ohm meter to the injectors. They all read 12.5-12.7 ohms of resistance. I am getting a smidgeon over 12 volts at the electrical connectors with a volt meter. I pulled the fuel rail, disconnected the coil wire, and had someone turn the car over. I can visually see all of them have a nice conical misty spray pattern. Its hard to see, but they all look like they are starting/stopping quite a few times a second. So I am pretty sure I don't have any fuel issues. I have also tested my ignition module and received correct voltage at it. I also made a ground going from the intake to the coil bracket. I have visually inspected and cleaned up with sand paper any grounds I could see. I know the ground to the passenger side of the block is good as I had to repair this wire. Does anyone know of any other hidden/out of the way grounds?

Thanks for the help so far:

ZMAN