My SES light started to blink last night so I had it scanned this morning. The codes returned were for EGR (I need to have it tuned out as I removed it when installing Pacesetter LTs) and "Random Missfire."

It's my understanding that when the SES light blinks that's when the actual missfire occurs? I put the car up on jackstands earlier this afternoon and checked the wires (30k on opti and wires, 1 year/~3k mi on TR-55 plugs) for any burns. Then I noticed the #3 cylinder plug wire was lose on the plug, so I plugged it in and took the car out for a spin. Got halfway to the auto parts store and it missfired so I turned around and got on the highway and jumped on it. The car seems to run fine, and seems to missfire under moderate throttle at around 2-3k, or when downshifting.

Any tips on how to trouble shoot it further? I'm going to try to find someone who can help me datalog it as I don't have a cable. If it means anything the car seemed to be running a bit rich before the missfires started occuring so I suppose it's a possibility that the plugs are fouled?

Car:
1997 Camaro SS M6
154k miles
Pacesetter LTs, LT4KM, 3" ORY, 52mm TB, etc.
Headers were put on (had eldelbrock shortys before) Feb/March of 2010 at approx 151k which is when the plugs were changed out

 

Here's a clip of it in my garage with the door shut (I took this after as I was finished trying to see if the plug wires were arcing. I think the plug wires are fine. What's the next guess? Plugs? Coils? You can hear it backfiring as I let off the throttle.

[autostream]http://autostream.com/camaroz28/?page_type=firebirdplayerthumbnail&framepage=1703& transactionid=1315776677-99418585&posted_by=6SpdLT1Z_www.camaroz28.com&yout ube_video_id=Mujmrb25rEc[/autostream]

 

You mention "coils".... do you have an aftermarket multiple coil system?

 

Sorry, typo. No coil packs / LTCC / etc.

I was just looking through my maintenance docs (which go back to ~130k mi) and the coil hasn't been replaced though it is possible that it was replaced at ~120k mi when the 2nd owner replaced the opti.

 

Unfortunately with miss-fires you might as well check everything. My car had one, it got worse and I dug deep and found more than one thing causing problems. Fuel pressure issue [pump/filter], cracked plug porcelain, tired lifters.

-Dustin-

 

A scanner should be able to tell you which plug is misfiring. I have a smart phone that does it for me with the blue tooth module plugged into the DLC.

 

Just the scanner at the local auto parts store? Looks like they test coils also so I'm probably going to run up there and have my coil tested and the code rescanned.

 

Question: I blocked off the EGR tube from the PS manifold/header to the intake back when the PS shorty header was installed in 2007. I still haven't had the EGR tuned out of the PCM , and the EGR valve is still on the back of the intake manifold. Could this be causing it? A tune and removing the EGR valve was on my list of things to do this winter / next spring, just wondering if this could be causing the issue, and if so... why is this issue finally presenting itself now?

 

Don't know if the EGR is causing the problem, but if the SES is flashing, that is the sign of a misfire. Take it to Autozone or somewhere else that pulls the codes for free. Remember the code(s) and post them here.

 

Apparently autozone can't test our coil, but I scanned the car again with a code reader at O'Reilly Auto.

• P0300 - Random/Multiple Cylinder Misfire Detected
• P0400 - Exhaust Gas Recirculation Flow Malfunction

Obviously I previously had the P0400 code error and was aware of it due to my blocking off the EGR pipe from the PS manifold/header to the intake manifold.

Car seems to misfire between 1600-2500rpms under moderate throttle/load. Runs fine at upper rpms and idles fine.

 

Looks like I've got a burnt #5 plug wire.

Any suggestion on a new set of wires? These are MSD SuperConductors

 

I'd say MSD's if they weren't so damn expensive. On my beater car I run Oreilys cheap set. They are actually very nice for the money and made in the USA.

-Dustin-

 

Got a set of MSD's out for delivery today so hopefully she'll be running like new later tonight.