Spyerx

Question:

While doing some stuff debugging my engine fan issue...

Pulled all the codes and had a Cyl 1 misfire code stored in the ECU module. NO CEL, no weird engine behavior, car feels strong. (and like an idiot I didn't write the codes down before clearing)

So, started car with durametric connected, logging misfires, ran for 5-10 mins, revving car, idling car, etc. A couple (literally a couple) misfires were logged in that time, Cyl1 and Cyl 4 1 each. No more stored codes.

So, no codes are stored in the ECU after i cleared.

So question: watch and observe? Drive car with logging on OTHER elements? Replace coils, maf, etc proactively? Fuel filter is new, fuel isn't 'old'.

neanicu

A couple of misfire counters will most likely not trip a CEL,it all depends on the car's computer and how sensitive is set up.
Many times random misfires like that are ignition related...a coil that is acting up under load for example. It's not like it's easy in these cars to just go in and swap coils between cylinders to see if the misfires move,but that would be very indicative of the problem.
I would just leave it and keep a close eye to see if the problem returns.

Spyerx

i'm going to get a full set of coils and keep on hand as a first step, plugs are new (3 track days), I was looking at my records are coils were replaced 3 years ago and have, well, a lot of track time on them :-)
So may be do.

Replacing them is about a 2 hour job, most of that getting the thing up on jack stands, without side mufflers it's easy to do.

You know what.... just thought of this. When I had the shop do my plugs I also had them do a leak down and compression test on the motor (all PERFECT)... I'm wondering if those codes were thrown then!?! And they didn't clear them...

Anyway, will keep an eye on it. Car ran strong and perfectly 2 weeks ago.

Jamie@dundonmotorsports

Clear them, pull the codes again and see if they come back. If it isn't setting a CEL it has crossed the threshold count for the car to be concerned about it...