2004 Tahoe 5.3 1000rpm idle and harsh 1st to 2nd

[Clarko88]

Any help would be greatly appreciated.

 

[Chrismnj]

Did you do anything prior to high idle? Like cleaning throttle body?

 

[Clarko88]

Did you do anything prior to high idle? Like cleaning throttle body?

No I just bought the tahoe.

 

[Clarko88]

Tahoe. Has 135k

 

[Chrismnj]

Any DTC codes?

Edit

Does it only idles high when you have your foot on the break?

 

[Clarko88]

No... no codes.. I took it to auto zone and no stored codes. Hes the thing it only does it when I'm going slowly into 2nd

 

[Clarko88]

Any DTC codes?

Edit

Does it only idles high when you have your foot on the break?

It always idles high the lowest it has gone is 900

 

[Chrismnj]

Maybe try cleaning IAC

 

[Clarko88]

Maybe try cleaning IAC

There is not one on this truck

 

[Chrismnj]

There is not one on this truck

Oh I am sorry, you posted in 2015+ section

 

[swathdiver]

Any help would be greatly appreciated.

Get the idle squared away and that will probably alleviate the transmission symptoms unless it damages something.

Check for vacuum leaks and clean the throttle body properly and take it from there.

 

[iamdub]

Vacuum leak? Dirty/sticking throttle? Dirty MAF sensor?

*Edit
Simultaneous posts, James

 

[Clarko88]

Oh oops

 

[Chrismnj]

Oh oops

but @swathdiver and @iamdub have good ideas.

 

[Scottydoggs]

def start with a tb cleaning and check for vac leaks. vac leaks can cause a hard shift as well as a dirty maf sensor. you can clean it, only use maf cleaner tho.

you can clean the tb on the truck still, but all the carbon build up is on the back side that you cant see from looking it, so its best to remove it and clean it real good.

 

[iamdub]

def start with a tb cleaning and check for vac leaks. vac leaks can cause a hard shift as well as a dirty maf sensor. you can clean it, only use maf cleaner tho.

you can clean the tb on the truck still, but all the carbon build up is on the back side that you cant see from looking it, so its best to remove it and clean it real good.

I say to remove the intake manifold and clean EVERYTHING. The gunk in the TB is one thing, but all that oil and crud inside the manifold needs to come out, too. I used a few cans of Super Tech brake cleaner and cheapest bottle brushes Walmart had in the baby supplies section to clean the runners and insides of my brother's intake manifold when de-sludging his engine. Installation of a catch can is highly recommended to slow down the sludge from building up again.

 

[Clarko88]

I removed the throttle body and cleaned it and unplugged batterie and no change... I have yet to clean maf sensor

 

[Chrismnj]

I removed the throttle body and cleaned it and unplugged batterie and no change... I have yet to clean maf sensor

hate when that happens

 

[Doubeleive]

you may have to shotgun it and replace maf, tb, intake gasket and while your in there do the knock sensors (go oem on the sensors & harness and silicone them in) fel-pro makes a metalized intake gasket. Sometimes that's just what it takes and if your feeling froggy do the plugs/wires and maybe coil packs also then your good for long while.

 

[Clarko88]

you may have to shotgun it and replace maf, tb, intake gasket and while your in there do the knock sensors (go oem on the sensors & harness and silicone them in) fel-pro makes a metalized intake gasket. Sometimes that's just what it takes and if your feeling froggy do the plugs/wires and maybe coil packs also then your good for long while.