So I just replaced my wires and plugs on my 99 d2... I cleared my codes and all of my random missfire codes went away, as well as my 2 o2 codes...

However my missfire cylinder 4 keeps showing up...

What could it be?

My cat is making noise, could this be it?

Coil? injector? dead cylinder?

any direction would be appreciated!

Thanks

 

No the cats going bad wont cause a mis fire.

What plugs and wires did you use?

 

A cat making a rattling sound is showing it has burned itself up, if it is the cat on the passengers side that could be showing a long problem on the passenger side of the block but not be causing the current misfire.

 

Alright

So did a compression test and compression was 150 and holding... in cylinder 4.

Checked spark, spark appeared the same on cylinder 4 as it was 6.

cylinder 4's new plug was black and the other cylinders plugs are tan... very tan.

Any more insight would be appreciated!!!

Thanks

 

Get ahold of a scanner that can give you real time snap shots of your injectors, sparks/coil information and see if there is an issue there.

 

Hmm... so drive with it logging... nice... would one from autozone do it?

 

Nope, and you wouldn't have to drive with it, just find more of a high end scanner and with your engine running scan the different sensors and injectors for issues.
You may want to have a mechanic do it.

 

hmm... what should I ask the mechanic to make sure that they are able to adequately scan the rigg???

 

Honestly I would rather buy my own rather than spend $100 for someone to do it. What brand could I look for???

 

As far as the cat rattling, there is a problem with D2 cat heatshields that gets loose and rattles on the cat on the pass. side. So before blaming the cat, make sure that that heatshield is nice and thight.