Sorry for taking up your precious time chief, for a second, I thought this was a forum for people who needed help. Some of us can't afford a 110 dollar an hour repair bill. And since I have two kids and a morgage, having the ability to diagnose and repair myself is very, very important to me.

 

The plugs are new, and I had actually changed them after the issues started.

I visually inspected the plug wires. They are MSD 8.8's. they are the ones you can bend out of the way of the headers.

I have not had any overheating issues or loss of coolant.

The truck doesn't smoke or burn oil.

I did notice this morning though, that cyclinder 1 was getting like dozens of misfires (had the tool hooked up to it viewing live data), and the other cyclinders that were getting misfires, were only getting one or two. Could an issue in #1 filter to the other cylinders? I did swap the coil when I noticed this before, but I did not swap the injector. I have never removed an injector before, so I was hesitant.

 

And for the record guys, I appreciate every tid bit of information all of you have given me. I know the predator is an inferior diagnostic tool, but it's all i've got. I'm staying on top of this because I need my truck. For many of you, your truck is your toy, my truck is all I have. It's my toy, my daily driver, and my work horse. If you need an info swap, I'm a licensed Glock Armorer, I hand load ammo and precision shoot long guns, and I can get you a hell of a deal on a saltwater fishing charter out of myrtle beach, SC.

 

It could be the injector on #1.Did you happen to check the exhaust temp on each cylinder?I tried to find a vaccum leak spraying carb cleaner and had no luck.I used smoke and found it in right away.I had a leak by the #3 intake runner where it meets the head.

 

With multiple misfires on the #1 Cylinder I would suspect there might be an issue with the injector given that you already swapped coils. For piece of my you could OHM the plug wires and see if they all have the same readings and that that particular one is not any lower or higher then the rest.

Your supposed to do a leak down check with a scan tool and a fuel PSI gauge. You would prime the fuel system and pulse the injectors while watching the gauge and noting the drop in PSI. You would re-prime the system to check each injector. You would also have the option to do a cylinder power balance while cutting out each injector individually and noting the difference in RPM.

You could try un-plugging it and see if the RPM changes much. Do a good cylinder first and then do the suspected bad cylinder. get the little retainer clips off first so the plug is easier to get off while the engine is running. Your other option would be to pull the fuel rail and swap the injector with another cylinder and see if you have any change.

As you know this could be very dangerous. Very important to Do this out side!!! Not in the garage. It's best to be prepared for a fire just in case with a fire extinguisher. Do NOT use water, fuel will float on water. You can never be too cautious and its better to be prepared. No one has ever said they wish they were un-prepared for a situation after the fact.

Bleed the pressure off on the intake rail before you remove the injector. Take your time and lubricate the O-rings to avoid pinching them when re-installing them. Make sure the clips are secure when you re-attach them. Try to contain any spilled fuel and clean it up if you spill any. When you re-attach everything, Turn the key on but engine off for 10 seconds then off and inspect for leaks. Do this at least 3 times minimum before starting the engine. This will prime the fuel system before you start the truck and give you a chance to inspect for leaks. The more times you do this, the more confident you will be about safety. Remember No Leaks is the only acceptable answer.

 

OK, i'll try that this afternoon and see what i've got. thanks guys.

 

so, I bit the bullet and took my truck to the local shop to have it diagnosed. I got tired of chasing gremlins. Funny thing. The technician hooked it up, and checked everything. All the coils are fine, fuel system is fine to include all injectors. He said my compression was 100% in every cylinder, with no fluctuation what so ever. Plugs wires were fine. (even swapped them with new ones just to see) no intake manifold leak or vacum leaks what so ever. He said all my sensors were fine, and it definately was NOT a cam or crank sensor. Since he couldn't find a thing wrong with the truck, the diagnostic was FREE. But, I left the shop with nothing more than a narrowed down list of things it could be. I was left with, maybe the predator's tune, or the computer was failing. Remaining symptoms, i'm still getting random misfires on cyclinders 1, 2, and 7.

So, I restored the stock back up programming and removed the predator tune all together. Last time, I just took the custom tune out, and put the canned 87 octane tune in. The tech told me it would take about 20-30 miles for it to sink in. So, another 15 miles or so, i'm going to hook the tool back up and run live data, to see if the misfires are still there. If they are not, then the Predator CLEARY created this issue.

With that said, if it's not the predator, and the misfires remain, what the hell else could it be? I've eliminated everything, except the computer??????

 

now i'm getting a P1133 code. Didn't happen when I was at the mechanics place.

 

Check this out. DTC P1133 or P1153 I found it in this thread. https://ls1tech.com/forums/pcm-diagn...153-codes.html

Try clearing it and see how long before it comes back. What about the misfire issue???? Did that go away after flashing it back to stock???

 

good thread, but we've eliminated most of those issues. as far as the misfires go, they remain. I've put a good bit of miles on the truck since I restored the back up. Still showing up. Interesting read about the O2's though. I actually ready up on the switch to corvette O2, but there is such a mix in regards to rather that actually fixes the header issue. I've been debating about dropping the coin on new manifolds and stock cat set up and just reverse it back to stock. Still not sure about the misfires. EGR valve a little sticky maybe??????