I have an '02 EXT, have done the following mods:

K&N Cold Air Intake
Ganatelli Mass Air Flow Sensor
Edlebrock Ceramic Coated Shorty Headers
Custom Dual Exhaust (Manifold Back with X-Pipe)
O2 Sensor Similators after cats.
Superchips Cortex Programmer

When I first start it up, it idles low and slow like an old 70's Muscle Car, which is fine I had the Custom Exhaust loud and free flowing with that objective, however if you floor it from idle sometimes it lugs, spits, burps and farts, prior to it taking off.
When it is warm it usually evens out around 450-500rpm on the tach, with occasional blurps down below 250rpm then it coughs and revs back up to 500 rpm.

All this is fine, I can deal with it, i assumed there would be some issues with the idle after i opened up the exhaust like i did.

The problem is sometimes when I'm driving around in parking lots and such the truck idles way low, while i use alot of power steering and power brakes, and air conditioning, the engine doesn't lug, doesn't burp, doesn't fart, just shut off.

I don't know about you but i drive fast in parking lots, and when you suddenly turn the wheel and hit the brakes to manuver into a stall and you lose power, your truck doesn't turn or brake worth a damn.

After the first time i almost rammed some car in a parking lot i started to double foot the pedals when i am in parking lots and wherever i am at idle.

Thats fine to I can do that.

However I let other drive my truck (My truck and a friend always end up being the DD) and telling them that the engine might randomly shut off, and you will lose power brakes and steering gets them a little uneasy.

Any ideas?

My Eldorado used to do this, I never totally got the problem fixed. A good tune up may be a way to start... Check for leaks in the exhaust near the engine.

I don't have any exhaust work done, and I have the same problem. The burping and hesitation is a little annoying, but I can deal with it, but I recently put a flip down in my car, and I disconnected the battery while I was doing it, and when I hooked the battery back up, I drove about 2 - 3 miles, and it died like 5 times in a row in a parking lot. Then I started it and just let it run for a few minutes before taking off. I also have a K&N filter.

Since the parking lot, I've put a crap load of fuel system cleaner in, and it seems to have helped a little. There doesn't seem to be as much hesitation. Then again, now that I'm thinking about it, it may need new spark plugs. Either way, a complete tune up (with the REAL fuel system cleaner - not the $3 a bottle stuff from Autozone) should do the trick.

How many kms on your truck?? When i had my 02 EXT it used to do the same thing also, but i put on a new fuel filter and it
solved my problem of the low idle and hesitation.

I bought the truck in April of '08 with 60k miles on it, now it has around 92k.

When I first got the truck it would sometimes have the low idle and hesitation on the line but it would never get close to stalling, after I installed the Edelbrock Headers, and the full exhaust it got way worse.

I know there are no holes or leaks on my exhaust, it’s pretty new and is all welded.

As for a tune-up what do you suggest?

Less than 500 miles ago I changed the oil (5w30 Mobil 1) in the engine, and both diffs (75w90 Mobil 1) I recently (less than 6 months) installed new Bosch Platinum IR 4+ spark plugs, and since i have installed the spark plugs I have only filled up with Shell Premium Gas with the nitrogen cleaning stuff in it, as well as the occasional fuel injector cleaner bottle.

Well, after all that, the only things I could see as potential problems are maybe the fuel filter like 93si said, or maybe a dirty throttle body. With the headers, you're definitely moving more are, and if the fuel filter is clogged, then that could definitely start some problems. All it takes is one tank of bad gas to mess up a filter. Similar symptoms sometimes come from dirty throttle bodies. They sell stuff called 'throttle body cleaner' in a can at auto stores for like 3 bucks, and fuel filters usually cost between $10 - $20.

Suggest throttle body clean and fuel filter replacement as well. Sounds like you have never done it since you own it, so its time anyway. VERY EASY AS A DIY PROJECT!

Good luck and keep us posted

X2 on the TB cleanup! My 02 had the same issue with low uneven idle, that took care of it. I cleaned it while still installed, but I had to remove the intake a few weeks afterwards and it was really messed up on the inside also! You can check pics in the thread about knock sensor replacement.

I have an 02 thats having the same problem right now, i posted on it about a month ago and got a lot of the same suggestions so hopefully this helps ..... Mine started doing this a couple months ago, it drives me nuts. So far i have changed the fuel filter, fuel pump, TB cleaning twice, cleaned MAF, new air filter, new plugs, new wires. None of these has helped AT ALL. This weekend im going to bring it to have the alternator and the battery checked. Im not really sure what else to try - maybe coil packs??? i dunno but hopefully this saves you some time and if anyone finds the fix pleaseeeeee let me know

Clean the throttle body.
The 02 was notorious for idle control problems as the carbon buildup in the throttle gets worse.
The newer ones seem to tolerate it better.
The issue is called "coking" but basically it is carbon buildup behind the throttle plate that causes minimum airflow calculation errors and poor idle control.
Should fix it.

Here's a pic of my TB after a quick cleanup...

http://i438.photobucket.com/albums/qq102/sk7_1969/Escalade/Lade127.jpg

This is what was behind it after I had to take it off to remove the intake!

http://i438.photobucket.com/albums/qq102/sk7_1969/Escalade/Lade134.jpg
http://i438.photobucket.com/albums/qq102/sk7_1969/Escalade/Lade135.jpg

The carbon builds up a ridge behind the throttle plate, the plate moves back and forth to allow more air to flow.
When the ridge gets thick enough it blocks what the computer is trying to do and it cannot compensate, it thinks it is moving to allow enough air for the idle speed, but it doesn't.
That means not enough air and if throttle conditions are right you'll get a stall.

You have to clean the throttle very well, behind the blade!
Just like those photos!
:yeah:

Excellent photos!!!!

Thanks for the Photos and Info.
I wil ltry cleaning the TB and see if that helps.