My Beast (4x4 Suburban)

[oil pan 4]

Originally Posted by Sporty Modder

The engine feels very healthy when it is in closed loop mode (cold) once it warms up and goes into open loop it develops the misfire right off idle until I get some rpms, and only after sitting at a light for a while, then it clears up and runs great.

It sounds like a fuel problem. It does not sound like a ignition problem.
That has to be a sensor or sensor wiring or sensor connector problem.
Since it only does it in closed loop and it kind of clears up after running for a while in closed loop.
In open loop it should be running off the TPS, IAT and oxygen sensor.
In closed loop it adds Coolant temperature, knock, MAF.

If it was an EGT problem or leak it would happen all the time, if the EGR was stuck open all the time during closed loop it would likely stall.
An ignition problem would likely be worse on cold start up.

Do you have a scangauge?
If not you may want to get one.

Originally Posted by Varn

If you haven't done it put on new spark plugs and plug wires. You might want to check out the engine compression. Seems like I remember that some of the older GM v8s had trouble with cam wear although I may be thinking older models.

That reminds me, if you have a flat tappet lifter engine, do not use SM rated gasoline engine oil.

Originally Posted by Sporty Modder

replacing the clogged cats.

You should have just gutted them if you can get away with it there.

Correction:
I said "so is the second row", I ment that they weighted close to 100 pounds not that they were in mint condition. The 2nd row seats are in the back yard now and my dog sleeps on them untill I set them on fire and turn them in for scrap.

Sportymodder:
Where are all the attaching points for your roof rack?
I may pick one up some time and keep it in the garage for they 90% of the time when I wouldn't need it.
Untill then I will likely be populating the roof with more solar panels so I need to avoid putting them near roof rack attaching points.
Its goint to get to the point where I will have to have a roof rack if I want to put anything on the roof due to the solar.

[Sporty Modder]

Roof rack mount...
Rack side

Truck side


And a vid of my misfire.
http://static.photobucket.com/player...n/5d784b7b.mp4

[Varn]

Those hinge barrels won't affect your mileage. That is a heck of a roof rack.

[night9]

You could take off the grill guard and lights to save a little weight. I realize this may not be ideal for you and that it was mentioned because of areo before but its also a small weight factor as well. I know the new Waren bumper I put on my Jeep years ago was almost double the weight of my original bumper. Just my .02$

[oil pan 4]

Originally Posted by night9

You could take off the grill guard and lights to save a little weight.

Pull it off for better aero and put it on CL to get a little cash.

[Sporty Modder]

(Quote)the push bar has saved the front of my truck once, (small deer)it is staying on, I may try to improve its aero though.(Quote)

The roof rack is awsome, I am thinking about pulling the barrels and selling the roof rack. My wife and I have put lawn chairs up there and watched games, great vantage 6ft in the air.

[ecomodded]

It is a perfect set up to build off of.
The flat face of the truck could use some streamlining.

[Sporty Modder]

On the way to work yesterday, I noticed more tire noise than before, =less wind noise
Also did a dirty coast test, day before lost 5mph coasting down my hill, without the rack lost 3mph.

[Sporty Modder]

When poking around under the hood today I found a open vac port on the (correction) egr solenoid, I caped it and will see if that affects anything, there are two ports on the back of it and one on the front, front goes to Tb, back goes to egr. Also grounded my coil pack, and removed my front mud flaps.
Looking under the front end she can def benefit from some gap filling.

[Sporty Modder]

It is running better, still not 100%.