motor stumbles in morning

[dwmmatt23]

i need some help here, had my car for 5days now and it pisses me off in the mornings. when i first start it up after sitting all night the motor will stumble for about 30seconds to a minute and then be fine. yesterday it did it and the check engine light flashes twice and today it did it but no lights. and after its warmed up for a minute it goes completely away and is fine till the next morning. is an 01 z71 tahoe with the 5.3 and @89k on it. any help so i dont have to have a shop diagnose it 10 times before the figure it out.

 

[92__silverado]

I just had the same exact problem on my 03, i made a thread about it. On cold start the motor idles terrible will stumble, shut it off and restart or drive it for a few minutes it goes away. Let me guess terrible gas mileage too? I was getting 7 miles to the gallon. Took it to a friend of mine and put it on the computer. Had 3k misfires on cylinder 1 and 5k on cylinder 3, right next to each other. It was an intake gasket. Took it back to the dealer I bought it from since it had a warranty, was without it for a week while the chevy dealer fixed it. Just got it back yesterday and everything seems great. Hope that helps.

 

[dwmmatt23]

I just had the same exact problem on my 03, i made a thread about it. On cold start the motor idles terrible will stumble, shut it off and restart or drive it for a few minutes it goes away. Let me guess terrible gas mileage too? I was getting 7 miles to the gallon. Took it to a friend of mine and put it on the computer. Had 3k misfires on cylinder 1 and 5k on cylinder 3, right next to each other. It was an intake gasket. Took it back to the dealer I bought it from since it had a warranty, was without it for a week while the chevy dealer fixed it. Just got it back yesterday and everything seems great. Hope that helps.

ive only had mine 5 days and no warranty with it. drove it back from LA and with half hiway and half city driving i got @14.5 mpg. just filled it up again so ill see what it gets around town but dont think it can be that bad. is there anyway of having it checked to see if thats what it is? would be just my luck to have to replace that

 

[TIM Z]

Yep, 92 Silverado is right, its the intake gasket, not hard at all to change.


Air is read by the MAF but since the intake lgasket is bad the engine is getting unmetered air also and isnt compensating for thus your poor idle and drivability.

Its not that bad , dont let it bug ya.

Go get the updated gasket set and take off your intake, replace gasket and Enjoy your new ride!

Its basically the only thing that goes wrong with these motors.

 

[92__silverado]

We put it on the computer and saw the misfires on cylinders next to each other. I guess a sure way would be a leak down test. Some of the guys here will hopefully chime in to help.

 

[dwmmatt23]

just got back from a very cold weekend in lake tahoe, was wanting to see how my truck ran in the morning at first start up in 20 degree weather, and it was stumbling alright to the point this time where it would die. i had to keep it up aroung 2000rpm to keep it from shutting off. sounds like intake manifold gaskets for sure to me, ran fine once it warmed up. what do you think? ive cleaned the throttle body and put new air filter in, if everyone agrees im going to go ahead and replace gaskets, or try something else if any other ideas

 

[jhellwig]

Have you done plugs and wires as something simple? Mine ran rough for a little bit on start up till I replaced the factory plugs with 83k on them. Might be worth a try.

 

[TIM Z]

Replace the gaskets!!

Any codes?

If so post them.

 

[dwmmatt23]

Replace the gaskets!!

Any codes?

If so post them.

no there hasnt been any codes, yea im just going to do it. im getting 10mpg around town and 14 on freeway, i was getting better mileage with my lifted 2door on 35's