Check engine light
 

Mine came on yesterday. Plugged the SCT in and code says Random misfire detected. anyone had this yet?
31,000 miles on the car, Is it time for a tune up? new plugs etc? I do not know a lot about engines, but can change plugs if thats all i need to do.
What else could it be? any input will be appreciated.

Thanks

Could be a lot of different issues. The cheapest would be to swap coils on the misfiring cylinder and see if the misfire moves. If it does move, replace it. I typically replace all of the coils and plugs for good measure. If you can and it's still under warranty, put it to stock and take it in.

with headers and catted X, cant really put it back to stock. and not sure what one is misfiring, it just said random misfire detected. Guess i will change all of them and go from there. Thanks

I meant the tune. Idk how they'd feel about exhaust but some dealers are more lenient than others.

Have you recently changed your clutch?

Sometimes, I wish the car had a Clutch...

Have you changed the converter recently?

Weird. I went to downshift mine today from 3rd to 2nd and my car hiccuped and flashed the check engine light just for a sec. Back to normal after that.

Nope... Happened 1st a few days ago, I changed the tune that I have been running for over a year "93S" to the 93R. I had been so happy with the 93S I forgot about the 93R, so I tried it, code came in after 10 min of driving. Put the 93S back on, code went away, then 2 days later came back yesterday.
Last night, I loaded a different tune from different company, drove to and from work today with no issues yet, but is still idling a little rough.

Clear the KAM and do an idle relearn and you'll probably be good

I will try that when I get back in town.. One thing I did notice before I left, It looked like one of the hoses going to the Moroso air/oil separator was collapsed in one spot.
I am definitely going to get better hose to change that out, but could this be what caused the random misfire code?

Not sure about that but IF you had changed your clutch or converter you should do a misfire profile correction procedure at the dealer.

Loose crank position sensor maybe?

This...common issue on the coyotes. You could also pull a plug to see if its fouled. I know mine were fouled out bad from the Trackey programming running lean up top.

Mine got a steady Check Engine Light two days after the engine was replaced. It came back with random misfire codes for various cylinders. The dealer tech had to do a 'crankshaft position relearn' process and that cured it.

PS - I don't like your 'idling rough' comment because that was the first symptom of my piston letting go. After about five miles of rough idling, the CEL came on steady, then the next morning it began flashing. The piston on cylinder 8 had cracked the top ring land. Hope yours is something else.

informative post.

.

Hmmm. My car had some crankshaft historical code brand new when I hooked it up to my scanner. I think it said relearn.

Thanks for all the input guys. I just got back in town late last night. Took the car down to Brenspeed this morning. They couldn't find anything wrong and the check engine light never came back. I figured while I was there, had them dyno tune it. 384.5 RWHP and 364.5 TQ in 97 degree heat. The last pull was 14 HP more than the 1st. I wasn't really concerned about the numbers, just wanted the tune dialed in better than the email tune. Car is running better than ever.

http://i46.photobucket.com/albums/f1...antha/Dyno.jpg

Set it all back to stock. A good day worth of work but its worth it if your going to need a motor. Not saying you wheel, but it wouldn't hurt to drive around stock w/ stock tune and see if the issue still exist on the stock tune. If so, take it in under warranty once the light comes back on.

Okay nvm. I didn't catch there was a second page to this post lol. Glad its running better.

Mine came on for the first time in a about 5k miles. Ironically the day after I took it to the dealer for an oil change and 20k "check up" whatever They did me ok. Went off 48 hrs later (Monday Morning) So I guess I won't take it in. Don offered to hook it up and check the code at Kellers. Never did