99 tahoe 4WD sluggish acceleration, rough idle, misfire.

[pcummings32]

i recently bought a 99 tahoe 4WD 5.7 vortec from a friend and its having some issues. at first it had a cylinder 6 misfire. i changed the plugs, wires, and cap and it seemed to be better so i put it on a code reader and cleared the code. now it feels like it could possibly be missing again. also it runs rough at idle and in park. it kind of bucks and shakes but its very mellow. nothing intense. also ive began to notice over the past couple of weeks that it shifts weird. as i accelerate it gets to the point in which its supposed to shift and begins to shift, then theres a slight hesitation and all of a sudden it catches or grabs and the shift is a success. this is usually just from first gear to second gear. it seems to be fine first thing in the morning when i start it up and then as it warms up it seems to get worse. im a car audio guy, not a mechanic so i have no clue where to even begin. ive talked to a couple friends that have made suggestions here and there but id like some second opinions before i do anything. please help!

 

[ChevysRollin]

Tried cleaning your body throttle?

 

[ChevysRollin]

If you do not know how to do it I can make a video to show you. May help others as well if they do not know what they are doing. I just cleaned mine today. Should of made it while I was cleaning it but I did not :whymewhyme:

 

[pcummings32]

i dont know how. a video would be extremely helpful. any other thoughts or suggestions?

 

[ChevysRollin]

I will make a video in the morning or if I can I will try to find you a good video. Its a simple task.

 

[clkelley]

Have you changed the oxygen sensors? That might help the "miss". As for the tranny shifting, changing the fluid and filter would probably help with that.

 

[ChevysRollin]

Here is a video I found...this should help. It will be similar as far as parts. You should be able to figure it out.

http://www.youtube.com/watch?v=41yFXjibtLY&feature=related

 

[pcummings32]

thank you all very much! ill let you all know what happens

 

[Arcane]

try to remove idle sensor and put your finger in the hole with engine on, if idle would come back to normal, then your idle sensor is bad. You have a scan tool, what can it show accept errors? Misfire could be caused by many reasons. The main thing is that fuel\air mixture is above normal and your main target is to find out is that air or fuel. Bad fuel injector, bad fuel pressure regulator, air sucking cos of worn out gaskets and on and on......
I helped a friend of mine, he had a constant cylinder 3 misfire. Whe changed cap,rotor, plugs wires and nothing happened. Problem was in spider, injectors were so dirty and worn out that almost aal injector tabs were broken while replacement, few injector tubes were leaking as the pressure regulator also. And we spend 4 hours to clean most of the carbon from the upper intake. Replaced it on a new style multi port fuel injector spider and problems gone, fuel ecomony back to normal and everybody happy. And he wanted to rebuilt the engine, spent few grants for it.

 

[Tieedekolwe]

Thank you for*good*communication.
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