99 Silverado 2500 6.0 cutting out... Tuner problem??

[blackclouddiesel]

I have a U7198 for my 99 silverado 2500 4x4 ec/sb with 4.10s. I have the diablosport tune with the following adjustments.

-5 injector slope.
-5 power enrichment.
+2 on spark.
154.99 speed limiter.

My problem is that every once in awhile when I step on it to pass the truck acts like it is getting no fuel. I am getting 0 KR when this happens as well. It doesn't do it all the time, but when your passing a semi on a 2 laner up a hill it sure is'nt fun when it does. I thought that maybe it was a fuel pump issue, so I replaced my fuel pump & filter. The truck also has fresh plugs & wires. I did download my original back up & couldn't get it to do it so Im thinking it may be the tune... Any help would be greatly appreciated as I would like to get this resolved as I have to move in a couple weeks & pull a 7000 lb load 500 miles.

Also, Is it ok to leave the diablo tune on my truck while towing heavy loads? I have a few 7% grades I will have to climb that are a few miles long.

[mikel]

Get a log of this happening.

The tune will be fine while towing.

[CANUCKPREDATOR]

If you put the stock tune in, does it do the same thing?

[blackclouddiesel]

No. I have'nt gotten it to do it with the stock tune. I will try to get it to do it while data logging. It only does it occasionally, it just really sucks when it does happen. lol

Thanks

[blackclouddiesel]

I also noticed while going through my other posts that Lew recommended not advancing the timing anymore. I will reprogram that back to 0 tomorrow.

[mikel]

That may be the issue.

[blackclouddiesel]

It did it again today, but of course while I wasn't in Data Log, but I was monitoring some RTD. I noticed all cylinders were misfiring, tps% was accurate, LTFTs were in the 2-5%+ range under WOT. Someone else said that it is probably my coils, but how likely is it all of them would be cutting out?? It feels more like a fueling issue to me... Anymore ideas? I have another complete 6.0 motor that I may swap the coils off of tomorrow.

[06MonteSS]

plugs, wires ??

[sickREDsierra]

plug a fuel pressure gage into the schrader valve on the rail, and check it at idle and revving. if fuel isnt the problem, most likely it is spark. could have cracked porcelain on a plug, faulty wire, etc. a quick/easy way to dtermine a dead cylinder is borrowing a pryometer from a parts store. shoot each cylinder and see which one is colder. there are also all kinds of spark checking devices and voltage tools to monitor coils/ignition.

when is the last time you cleaned the MAF ? just want to throw in all the small things that can collectively cause issues. oily MAF or dirty MAF can cause rough running at WOT and idle.. and its good to have it clean either way.

[Morgoth]

Especially if you're running a k&n....

[blackclouddiesel]

plugs & wires are new as well with about 5k now. Its been about 20k since the MAF sensor has been cleaned. Will do that now. Whats weird is it only does this once in awhile, then runs just fine... Ill see if I can track down a fuel pressure guage. What psi do these run at? 40-45??

[blackclouddiesel]

plugs & wires are new as well with about 5k now. Its been about 20k since the MAF sensor has been cleaned. Will do that now. Whats weird is it only does this once in awhile, then runs just fine... Ill see if I can track down a fuel pressure guage. What psi do these run at? 40-45??

At this point im thinking its a tuner issue since I cannot get it to do this on stock programming.