Annoying miss

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Oct 9, 2013 | 05:04 PM

seevi

Thread Starter

Burning Brakes

Joined: Aug 2008

Posts: 802

Likes: 6

From: Oro Valley AZ

Annoying miss

I recently replaced lifters in an LS2 with a Comp XER273h14 cam. Had a miss before and afterward. Replaced NGK TR6 plugs and wires with OEM replacements. 98% of the miss went away. Thought it may be a vacuum leak and sprayed the entire air intake system with starting fluid and there is no change in engine speed. A scan reports all but one cylinder has a random misfire, with occasional CEL. Scanning the "Misfire Failure" PID, reports 0. There is no misfire over 2,000 RPM, or WOT. Any suggestions?

Oct 10, 2013 | 11:14 PM

Tikiman12

Drifting

Joined: Jun 2006

Posts: 1,730

Likes: 4

From: Delray Beach Florida

I had this problem. I put new spark plugs in which worked for about a week then I got a small miss like you have now. I put in a brand new battery, that fixed it.

Oct 11, 2013 | 09:25 AM

truckplay

Melting Slicks

Joined: Oct 2010

Posts: 2,220

Likes: 16

From: Sugarhill Ga

did you check the cam sensor while you had the engine apart ? was it oily or could it have been damaged ? did you change the valve springs ? are you sure the injector harness and coil harness are plugged in & locked?
You may want to CAREFULLY clean the MASS with MASS CLEANER.

Oct 11, 2013 | 09:53 AM

seevi

Thread Starter

Burning Brakes

Joined: Aug 2008

Posts: 802

Likes: 6

From: Oro Valley AZ

Quote:

Originally Posted by Tikiman12

I had this problem. I put new spark plugs in which worked for about a week then I got a small miss like you have now. I put in a brand new battery, that fixed it.

Yep, did that too.

Oct 11, 2013 | 09:57 AM

seevi

Thread Starter

Burning Brakes

Joined: Aug 2008

Posts: 802

Likes: 6

From: Oro Valley AZ

Quote:

Originally Posted by truckplay

Cam sensor seemed OK. Changed springs when I installed the cam. Harness seems OK as well. Will clean MAF this afternoon. Thanks for your suggestions.

Oct 11, 2013 | 04:32 PM

KB9GKC

Burning Brakes

Joined: Jul 2008

Posts: 923

Likes: 37

From: Green Bay Wisconsin

Hello,

A compression test will let you know if your valves and rings are sealing!

Douglas in Green Bay

Oct 11, 2013 | 04:56 PM

vette6500

Pro

Joined: Jun 2005

Posts: 693

Likes: 2

From: Los Angeles CA

seems like it's mainly a spark / fuel issue.
since you've tackled the spark issue, seems like fuel injectors are next.

i think running the trusted concentrated techron plus in 1 or 2 consecutive fillups to see if it's just clogged injector seems to be the cheapest/easiest thing to try first.

good luck.