Well i decided it was time to get back into a LT1 car and found a good deal on a 97 Ws6 bone stock with a ripper shifter.picked it up about 2hrs away and on the way home i noticed the SES light flashing at me,though o'crap already got problems lol.the car actually drove just fine tho,couldnt feel any hesitation really and it made it home with no issues. I hooked up the trusty tech2 as soon as i got home to find it was #7 and #4 misfiring equal times,so here is what ive done so far trying to track down my problem:


- found #7 plug wire was burned up so went ahead and replaced all the plug wires but the mis didnt go away.


-pulled #7 plug and it looked normal,no wear and looked to be burning good.it was a NGK TR5 so a stock heat range plug.


-checked for spark with my tester and it was getting spark just fine to #7


-thought maybe it was and injector so checked the wiring to #7 and #4 with a noid light and all was good there,also swapped around the injectors to try and make the mis chase but it didnt move.


only thing else i can really think to do is move #7 and #4 spark plugs around to see if maybe there is a problem with the plugs like a hair line crack.or could it be in the opti cap or even the opti its self???usually opti problems cause all cylinders to misfire but im not one to rule anything out. any advise or ideas would be awesome!thanks in advance

 

recently had the same trouble with my 96. replaced the distributor and it went away. if it's not that, try the fuel pressure regulator. lookin at a $400 from summit.

ah, but before trying that, have you reset the errors after changin the cables, the boots and cables aren't touching the headers? it could be a simple 10 minute drive down the road to ruin your cables or cause a misfire.

 

I havent even had the car out on the road yet just started the car on the lift after all my trial&error sessions with the tech2 hooked up to see if the misfire was still there and of course it was.

 

well guys i moved around plugs just rule that out and im still missing on the same 2 cylinders,today i replaced the opti and still no change.any ideas guys?stuck valves?im at a loss!!!!

 

have you tested the fuel pressure? makes sure the miss isn't ont he fuel side, perhaps you have some trouble with your EGR(if that's still wired up)

 

Roll through these....(1996 factory manual)

http://www.ace1252.com/1996_Z28_Fact...TC_P0300_1.JPG
http://www.ace1252.com/1996_Z28_Fact...TC_P0300_2.JPG
http://www.ace1252.com/1996_Z28_Fact...TC_P0300_3.JPG
http://www.ace1252.com/1996_Z28_Fact...TC_P0300_4.JPG
http://www.ace1252.com/1996_Z28_Fact...TC_P0300_5.JPG

 

Checked the valve adjustment?

 

The valve covers are coming off tonight so i can check the rockers out and ill let you know what the verdict is,and ACE1252 thank you I will definetly go thru each of those steps.

 

adjusted all the valves just now and that didnt help so i checked fuel pressure and that checked out fine,also ran a compression check on the misfiring cylinders and they both had 180 and held just fine.

 

The compression check should logically have compared the two misfiring cylinders to the 6 healthy cylinders, not to each other.

 

The PCM is using the CPS to detect these "misfires" if you actually have any. Perhaps the reluctor wheel for that has an issue where those cylinders firing events correspond. Another option is to borrow a PCM and atleast eliminate that as a problem, in case the issue is internal to the PCM.

 

Check out the voltage that the ignition coil produces. I dont think its that.

Pull an injector look for clogs or swap around injectors