I have a 2000 Chevy Blazer 4.3 that has hesitation. Now its very drastic if the trucks cold and i need to move it quick. I hit the gas and it seems to studder badly or fall on its face then I have to hit the gas more then it lunges and goes when completely cold. It does it until it warms up some and still does it slightly from an idle and that's it. It has new plugs about 6,000 miles ago, wires, distributor, fuel filter, air filter, throttle body cleaned, MAF cleaned all within about 15,000 miles. I had recently put new motor in about 6,000 miles ago but don't remember if it did it with my old motor or not because it did the throttle bod mod along with this new motor. I have a cam and some other minor internal motor work supporting the cam, header back exhaust, a cold air intake, and a tune. She runs very strong other than that hesitation. Ive also checked my trans mounts and everything's good, I thought they could be worn out and could be torquing up but they are fine. Any help please? Thank you!

 

Did the problem start right away when the new motor was put in or did the problem start recently?

 

Sounds like it could be a dirty EGR valve. I would try cleaning it to see if it helps, if not then do a fuel pressure and leakdown test.

 

It always did it with my old motor too but it thought it was because normal with the throttle body blade that comes stock and doing the mod would help which it just helped with throttle response not the hesitation.

Ill have to look up on how to clean the EGR valve and try that. It could be a leaking injector since it did do it with my old motor also so i will have to look into that

P.S. It also does start up a little hesitant from the start compared to when warmed up or recently ran a couple hours ago etc. I have a feeling that can relate also

 

Any other info anyone? This alSo came to mind, I'm reusing the intake manifold off my old motor which also had this problem and as I said it starts a tad funky then Rpms climb as already said. Could it be a leaky injector?

 

Original SCFI spider? Have you tried running a double 20gal treatment of Chevron Techron Fuel System Treatment Plus through a tank?

 

Yeah its the original spider. No i haven't ran that. Ive had some Lucas fuel injector cleaner etc ran through it but anythings worth a try. Can i get that at any auto part store and im assuming its stronger than a normal fuel system cleaner?

 

Last Post 07-25-2012

You must have figured out the problem or gave up...
If so can you tell us what you did to fix the problem?

Thanks in advance

 

i have the same problem with my 2000 blazer, new cap, rotor, fuel pump, cleaned maf, etc. any solutions greatly appreciated.