hey i have a 01 chevy blazer 2 door the problem im having is hesitation and pop through the intake under a load. The only time this hesitation happens is when i fill the gas tank until it hits under half a tank it will start to run fine with no hesitation. the charcoal canister is empty no gas in it i cleaned it with compressed air. then i just cleaned the purge valve i believe its called its under the hood. it still does it i don't like driving it with the hesitation but its the only vehicle i have. i was wondering if any one has had this problem and could help me out thanks. im pretty sure its something to do with emissions. the things i have done to it are intake gasket, plugs and wires , distributor, fuel filter , fuel pump test pressure is normal and egr tube.

 

Did you test the fuel pressure at the rail or at the pump? Do you remember your readings and how much leak down there was? Are there any codes and have you cleaned the MAF sensor?

 

im not sure my mechanic did the pressure test and i did clean the maf forgot to write that.

 

Was the problem there before you replaced all those parts, or were you trying to fix it by replacing the parts?

Sounds like a lean condition or incorrect camshaft retard. Are there any DTC's in memory or pending? Does the Service Engine Soon light come on and shut off with the bulb check? Is the Service Engine Soon light on while driving?

 

its been doing it since i got it and no all the parts i did the truck needed. the fuel filter fixed it for about two months. i don't have any engine codes that come up i had one a while ago so i did o2 sensor and it fixed the engine light. i think its a clogged catalytic converter.

 

An exhaust restriction will cause a problem all the time, not intermittently like you describe.

Fuel delivery is critical on these engines, and if it's not within specs, you will have problems. Checking fuel pressure and leakdown is free, fast, and easy to do. The results tell us the overall condition of the fuel delivery system, (fuel pump, fuel pressure regulator, etc). Most auto parts stores rent fuel pressure testers for free, and sell them for ~$40. When you have one at your disposal, let us know and we can walk you through the procedure, takes about 15 minutes.

EDIT: Replacing the lower intake gaskets requires removing the distributor: When it is reinstalled, camshaft retard MUST be checked and adjusted with a capable scan tool. Incorrect camshaft retard can cause a hesitation and induction, and not turn the SES light on.

 

could have a lifter collapsed.

 

i didnt do the intake gaskets im assuming my mechanic checked the timing and my mechanic did check the fuel pressure because i knew the fuel systems in these trucks are bad he said its where it should be. i wish i asked him about the pressure numbers all i know is he said its fine that was 2 or 3 months ago he tested it only time it hesitates is after filling the gas. it just started doing it the last 3 fill ups.

 

Intermittent or hard faults in the fuel delivery system can develop in a heartbeat, a lot can happen in "2 or 3 months". That's why we need fuel pressure and leakdown results. Timing is not adjustable on this engine. Camshaft retard is adjusted by slightly turning the distributor. Turning the distributor does not affect ignition timing. Not saying they didn't check it but, there are a lot of techs that are unaware of the adjustment. They assume that if the distributor gear meshes correctly with the camshaft, that it's good enough, and that's just not the case. Too much "assuming" going on There are several extremely knowledgeable members here that know more about Blazers than most shops know. You're asking for help and we're offering it, don't discount suggestions unless there's data to back it up. We're glad to help, but ya gotta work with us

 

alright i see how do i do the pressure test or should i just Google/YouTube it i can rent one from a shop in town.