Hey all,

I feel like I've been starting a lot of threads on the forum lately. Kinda feel like that .

So I've been hunting down this misfire. The code reader at O'Reilly's told me the car was throwing a code for a misfire on cylinder #6 and a code for a bad EGR valve. My mechanic and the O'Reilly guy told me that the EGR is probably causing the misfire so I replace the valve, nobig deal, and the CEL turns off. So I drive a little, let the engine warm up, hit the highway, floor it and the misfire comes back. Grrr.

The misfire happens when I floor the accelerator and under gradual acceleration. I first noticed it a couple of months ago when I put fuel injector cleaner in the tank. I drove around for a couple of days and then one day merging onto the highway the engine started to stutter and the CEL starts blinking. Around the same time my CV axles began to fall apart. CV axles have since been replaced.

The only other thing I can think of is that I replaced the spark plugs after the misfires had started. The gap on the plugs was ~0.057" instead of the prescribed 0.060" but I felt like it was close enough.

So any thoughts on what could be causing it?

Thanks a lot guys, this forum has been a huge help to me and my automobile adventures.

 

You have a code for a specific cylinder. You are down to plug, wire, injector, coil or even a vac leak.
A gap difference that small I don't believe would cause a mis-fire in only one cylinder if it was a problem. Also, if the plugs you are using are BOSCH, dump them and get NGK or AC Delco (I have had too many bad experiences with even new BOSCH plugs to have any want to trouble shoot a misfire with them).

A coil typically causes two cylinders to mis, but if there is damage to one tower, it could cause 1 cylinder to fail.

One thing you can do to test is move the coil to another position, see if the misfire changes cylinder. If not, swap injectors, again, see if the failure moves.

 

Ive delt with five bad coilpacks that were only dead on one cylinder. The three that came with my car(one did it every other month till i replaced all three) one when i grabbed my first set of l67 coilpacks(yes l67 coilpacks go bad) and one on a friends century. If thats what it is dont worry, theyre $25 brand new(so dont let anyone con you into paying more than that, jy tried selling me one for $40 used once)

 

I tend to favor OEM coils over the aftermarket. It's rare, but I have had coils fail (in all the cars I worked on that use these coils, I think I've had 3 coil failures and one was the aftermarket replacement). Due to the rare fail rate, I favor salvage coils over a new parts store one. But as L67ss mentioned, don't get fooled in high prices.

But first, try to isolate what the issue is before throwing parts at it.

 

It sounds to me like a clogged injector. You can verify this by swapping the #3 injector to a different cylinder and see if the misfire code follows. If it does, either take the car to a shop that can professionally clean the injectors or replace the injector.

 

Thanks for the replies everyone, I'm going to try looking for it this weekend. I'll let y'all know if I figure it out.

 

Hey everyone not to thread jack but I have a similar problem.. I replaced my plugs with NGK iridium plugs and ac deloco wires and since then my car has been running strange on first start and misfiring. I checked the codes and I think I had one for egr like OP but I haven't done anything with that, I had another code for cylinder 6 misfire and replaced my coil packs which helped but still missing.

It happens under about the same conditions and it stutters under about mid acceleration. I dont understand why it would start happening after changing the plugs but I have had some people mention it could be something unrelated like a fuel filter...

 

Had a similar issue awhile back that turned out to be injectors and was rectified with, in my case, Lucas injector cleaner through the tank. But during the search, I stumbled across something call OBDcom.com and got the software and cord for my laptop. It helped narrow things down since I had real-time graphs and info while driving down the road, with the ability to clear and read the codes immediately. Not a company owner, just a fan...

 

Ok so I'm pretty sure what happened was that I put fuel injector cleaner into the tank, it knocked out a bunch of gunk which then got stuck in the 6th cylinder injector (as according to the ODB code I got). I tried a black bottle of STP fuel injector cleaner and nothing changed. On my last tank I used the little bottle of Lucas Oil cleaner that's rated for 25 gallons and I've had a big improvement. Just filled up yesterday and and threw in another bottle of the stuff and I'm hoping that I can dissolve this little stuck sucker.

Interesting product, thanks for the tip. When you bought it did they include a connector cable that would hook up to your laptop? I'm currently looking around at various open source and pay to own ODB 2 softwares. Will try to update.

 

Glad it helped you like it helped me! That software for my laptop ran about $99 and came with the OBD2/usb cord included. Long enough to put the puter in the passenger seat while I was driving. All the best to you!