i have 4.3 vortec blazer. driving home from work on the freeway going 70 it bogged out on me and wouldnt go over 45 mph or go over 3500 rpm. ive switched out my catalytic converter put a flowmaster on while i had all that stuff out. thought it was my cat originally. it was't. has 160,000 miles on it so i did a complete tune up. new distributor cap, plugs and wires. new mass air flow sensor and i have the same problem. i dont have a check engine light so i cannot do a diagnostics test. im getting a few different things from people here in town. im tired of buying and replacing parts that dont need replacing. some are saying a solenoid some say a clutch fan, none of that makes sense to me. anybody ever have the same problem or have any idea. im about to set the mother ****er on fire

 

When it bogged down did your engine temp go up also? Did you take a look at your oil? What you experienced is the same thing I did when my head gasket went.

If there is no coolant in your oil. I'd bet dollars to doughnuts that all of the highly experienced folks (I'm not claiming to be one of them) on this forum will tell you to start with a fuel leakdown test. This is just one of the recent threads that describes how to do this https://blazerforum.com/forum/2nd-ge...rt-cold-75428/ You will find a description how to do the test on page 3 of the link.

 

Sounds like it may be a transmission issue if it won't shift to a higher gear.

 

Did you have any problems with the abs light being on or the speedo not working? If so check your vss sensor on the trans output. That's the issue I had awhile back.

 

i fell your pain my wifes blazer did the same thing i replaced the converter with the same out come i got to looking at it and it would run fine til i got the rpm up here to find out there is a different size pipe in front of the converter( between the motor and converter).called the local auto parts store and they want 400.00.so i just cut it open cleaned it out and welded it back closed.if you have a welder and a grinder the only thing it will cost you is time and cut off wheel and welding wire

 

I would change the fuel filter.

 

Maybe it's the color of your Blazer! Well....we mentioned just about every other part of the truck...all the was left over was the paint color to cover the entire thing

 

I have a 00 blazer 4.3 the tack goes crazy and bogs down it seams like it does it under a load I have already replaced the plugs,wires,transmission speed sensor, crankshaft sensor, cam sensor, TPS. I have even checked crankshaft sensor for marks and found some so I also used shims but nothing any help please?

 

scan tool

 

I don't have any codes or check engine on! Even though my scanner would not pick up anything I had a friend mech put his high dollar scanner and it picked up cylinder six miss fire that's wen I replaced spark plugs, wires and also checked compression & cap and rotter they checked out good! Could it be the injector but would it also make the tack flicker?