Intermittent missing

**johngoodman** · 06-13-2015, 08:47 AM

My LS1 has suddenly started missing intermittently. It doesn't start until the engine warms up, and then I hit a high rpm. After that, it begins to run rough, even down to idle. After cool down, it's fine until it warms up and high rpm.
I've changed all the fuel filters, and looked at the plugs. I'm not getting any codes. I'm thinking that my next thing to do is one, or all, of these three:
Change plugs
Change plug wires
Possible clogged injector
Any opinions out there?

John Goodman

**pajeff02** · 06-14-2015, 01:44 PM

Is the SES light on? Have you scanned it for codes?

**johngoodman** · 06-15-2015, 12:21 PM

Originally Posted by pajeff02

Is the SES light on? Have you scanned it for codes?

The first thing I did. The light is working normally, and there are no codes. I'm narrowing it down to the injectors for now. I did notice that the Crankcase vent line on the rear had disconnected - that could possibly cause a lean mixture at high rpm, but who knows....
Thanks for the reply,
John

**2002ssslp** · 06-15-2015, 03:27 PM

I'm thinking coil packs.

**pajeff02** · 06-15-2015, 03:51 PM

Upon installing the new ignition wires - you should hear/feel one "click" at the plug and two "clicks" at the coil pack. Does not hurt to go back and double check your connections.

**johngoodman** · 06-16-2015, 05:28 AM

Originally Posted by pajeff02

Upon installing the new ignition wires - you should hear/feel one "click" at the plug and two "clicks" at the coil pack. Does not hurt to go back and double check your connections.

I'm saving the ignition wires for last, so that I can eliminate any fuel issues. I will check the connections again, Thanks for the hint. Turns out that I just got a call from the shop that cleaned, and tested, my injectors - they were in bad shape, and he had to clean them three times. I'm picking them up today.
Right now I've got another problem. One of the retainer clips on an injector was missing (may have never been there). I'd like to get a new clip, but the local Chevy dealer said that I couldn't find one within 100 miles (he checked). They haven't had that style since 2002. Forget AutoZone, etc. I might try a junk yard
John

**0rion** · 06-16-2015, 09:28 PM

search "fuel injector clip" at rock auto....you can buy the whole connector there for less than $10.

**pajeff02** · 06-17-2015, 02:38 AM

In light of the fact of your "dirty injectors" it would be a real good idea to run the TC-W3 regiman. Buy a bottle of TC-W3 2 stroke oil and run it at a ratio of 1 ounce per 5 gallons of fuel. The benefits of doing this include adding lubricity to the fuel, which nowadays has a 10% ethanol content, better mileage, and it also has cleansing properties for injectors, valves and combustion chambers. We have a lengthy thread on here and many members, myself included, run TC-W3 in their cars. In fact, I run it in all our cars including the daily drivers.

**johngoodman** · 06-17-2015, 05:42 AM

Originally Posted by 0rion

search "fuel injector clip" at rock auto....you can buy the whole connector there for less than $10.

I had tried Rock Auto before, but didn't realize that the search engine would find words, as well as the stated "part number."
They definitely have some that could work, I'll give them a try - Thanks.

Concerning the other replies - I'm reluctant to use any additives. The GF-822 filter/pressure regulator I use has a paper filter in it, and those injector cleaners are supposed to do paper filters damage. Also, I'm running 100 octane leaded fuel a lot, and I'm not sure the fuel & additive would get along.

John

**pajeff02** · 06-19-2015, 10:25 AM

Are you tuned for 100 octane fuel?

**35th-ANV-SS** · 06-19-2015, 02:15 PM

Originally Posted by pajeff02

Are you tuned for 100 octane fuel?

If not, that's probably doing more negative than good.

**pajeff02** · 06-20-2015, 04:23 AM

My friend with the Dart does this. We go to the track and he promptly dumps super high octane fuel into his car and starts making passes. I have tried to explain that he is actually hurting performance.

**johngoodman** · 06-25-2015, 03:52 AM

Actually, I AM tuned to 100 leaded fuel. I especially like it because it stores for a long time, won't foul injectors, and requires no additives.
By the way, I found the missing injector clip, so it must have dropped off on my table when i removed the fuel rails.
I replaced the plugs and leads with new stuff from Summit, but it's still doing it. That takes me to the coil packs. Is it worth testing for a bad one, or simply replace the whole set?
John

**pajeff02** · 06-25-2015, 05:22 AM

Swap the coil around with another one and see if the problem follows the coil.

**0rion** · 06-25-2015, 05:13 PM

It would be nice if you could narrow it to a cylinder to save some work. Are you getting codes for misfires?

**johngoodman** · 06-28-2015, 06:05 AM

Actually, I'm not getting any codes at all, but all I have is an ALDL connection. Swapping the coils around won't help, because I'll still get the missing, just on a different cylinder - that I can't find. So, I've ordered a set of 8 new coils. Should get them Tuesday. Got a pretty good price on e-bay.
John