I know im new but PLEASE help me with my truck problem
 

I have a 2004 chevy 1500 z71. This is my first chevy and it has been a really nice truck until now. It has 152,000 miles on it. About a year ago i had a engine code on my truck and it was the rear O2 censor and i was young and dumb and didnt think much of it so i cleared it with my programmer. Now I think its coming back to bite me in the butt. My chevy keeps diying on me. It dies on me when i let it idle or pull in my driveway (holding the brake to long i think). When at idle it will bogg up and down and after about a min of it bogging down it dies. sometimes it even dies when im truning at a intersection. so i figured i would unplugg the rear O2 sensor 4 days ago and thought it would throw another engine code but it hasnt, which i have no clue why. I have replaced my cats about a month ago thinking that might fix the problem but it hasnt yet. I aslo replace the air filter thinking it wasnt getting enoguh air but still hasnt fixed it. I'm also getting terrible gas milage because the truck is running rich i believe; it might be lean but i think its rich. The only thing that throws me off is that when i drive it on the highway for 10 mins or so it will run pefrect no matter what even at idle. Please someone help me i would like to get my baby back to running the way its suppose to. i would greatly appreciate it.

Take a look at your throttle body and see if it is all carboned up inside. They need to be cleaned periodically so, if you haven't recently, then get some throttle body cleaner and try to get as much of the carbon cleaned up as possible especially where the butterfly touches the inner wall of the throttle body. If it gets to bad it will act like what your describing. The carbon build up actually blocks the air which affects idle and off idle acceleration.

thanks Mr Shamrock. You were exactly right. just got done cleaning it out and it was bad. she runs like a champ again. thanks for being a genius

Right on Shamrock! Glad you got her fixed. Let me suggest to replace the O2 sensors anyways since they get lazy with higher miles. New ones will give quicker readings for the Air/Fuel mixture to be right. This will add performance and better mileage.

Since you are cleaning things, I'd suggest cleaning the MAF sensor as well. Get some CRC cleaner, give it a good soaking, and let it air dry.

Glad you got it fixed!

one more question. i know that the speedometer is a very common problem in that year of chevys and mine is messing up to. it is always stuck at 0 or sometimes its like 3 or 4 miles per hour off. i know that they gave a warranty out to fix it but i have to many miles. my local chevy dealership said it would cost around $400 to fix it. is there any way i could get around that like replace a part or buy a aftermarket one? or am i just pretty much screwed and need to pay the $400 to get it fixed?.

And by the way i highly appreciate all of taking the time to respond to my promblems. i will take a look into all of the stuff you guys have suggested. everyone has been a huge help.

The dash cluster has whats called stepper motors running each individual gauge. If your good with a soldering iron you can solder in new ones. If not, look on eBay and there are a few sellers that offer rebuild services. You shouldn't spend more than $100 and they will replace all the motors and any bulbs that it might need. I am getting ready to send my dad's 2005 Escalade's cluster in. You can drive your truck with it out so don't worry about the down time for your truck. It should only be a couple days before it gets back to you anyway.