My pickup is a chev silverado 5.3l (327) V-8.  Recently it has been hard to keep started/stalling.  I have to feather the accelerator to keep it started but then after it gets started and goes for say 10-15 mins it is fine.  It is like there is a choke on it wide open.  I get no service engine light.  it has ~115k miles on it.  Ive heard a couple different things it may be (fuel filter (ez fix), bad gas (ez fix), etc) Gimme your thoughts please.


thanks heaps!

You can check the IAC valve/sensor. That is similar to a choke in that it regulates the amount of air coming in while the vehicle's throttle is closed and warming up. Cleaning it with carb cleaner, but not brushing it or using a cloth on it, helps. It is usually held in with two small torx etc screws on the throttle body.

Quoted: My pickup is a chev silverado 5.3l (327) V-8.  Recently it has been hard to keep started/stalling.  I have to feather the accelerator to keep it started but then after it gets started and goes for say 10-15 mins it is fine.  It is like there is a choke on it wide open.  I get no service engine light.  it has ~115k miles on it.  Ive heard a couple different things it may be (fuel filter (ez fix), bad gas (ez fix), etc) Gimme your thoughts please. thanks heaps!

We have been seeing a LOT of this.  Changing the intake manifold gaskets will likely fix this problem.  YOU MUST USE FACTORY GASKETS as the part has been revised.  The old & aftermarket gaskets have red silicone, the revised part has green.  Here's what's happening:  On cold starts, the gasket is allowing air to leak in, and your IACV can't control idle speed.  As the engine warms up, the heat swells the silicone part of the gasket and the leak is minimized and the condition subsides.  You can change these yourself in about 4 hours.Good luck.

My 1999 Suburban had the fuel pump/sensor unit ($400 modular piece of crap) go at 125k.  Same symptoms.  Check the codes to see if the pump is done for.  When it dies on a family trip several hundred miles from home around Grant's Pass with 3 young kids in the back, it has extra fun factor - Don't ask how I know.  

Here's a copy & paste of a Confirmed Fix on a similar vehicle.  You can easily do this test at home too. Note the new part number & teal green gasket color.

   Confirmed Fix  
 
     
Vehicle Description:  2000 GMC Sierra 1500 5.3L, Vin T, Eng Cfg V8  

 

Mileage:  100131  
   

Customer Concern:  Engine misfires when cold. DTC P0300. The Mass Air Flow (MAF) sensor elements have been cleaned. Fuel pressure is OK.  
 

Tests:  1. Spray water on the underside of the intake manifold when the engine misses cold.

2. If the engine reacts to the water, replace the leaking intake gasket seals.

3. Replace the gaskets with the updated part number of 89017589.

4. An intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area should be replaced.  

 

Potential Causes:    Intake manifold gaskets
Dirty MAF sensor
Fuel pump

** Confirmed Fix **
Intake manifold gaskets
   
 

 
 

Diagnostic Codes:  P0300  

Tech Tips:  The updated replacement gaskets part number 89017589 are teal green in color.  
 
       
Author  What Fixed It /   Confirmed Fix
 
 

2/6/2008   2000 Chevrolet Silverado 1500 5.3L, Vin T, Eng Cfg V8
Intake manifold gaskets
vacuum leak @ intake runners 2&6. new intake gaskets fixed problem.
 
 

tHANKS FOR ALL THE HELP

P-0300 is a "Random Multiple Misfire" code..... 301, 302, 303, 304, 305, 306, 307, 308 and so forth tell which cylider has misfire detected.

Quoted: tHANKS FOR ALL THE HELP

Did you fix it?

Ya i did. the easier way.  may be only a short solution but it is working for now.  took out the IAC valve and sprayed it w/ throttle body cleaner and changed my fuel filter again. working alright for now. if problem persists again then ill do the intake manifold gasket.  My father in law is a mechanic and he lives 90 miles away, so ill take it to his shop and DIY if i have to do the manifold. He has every tool snap on makes in his shop...is UNGODLY really.  thanks again all!