View Full Version : 4.3 vortec v6 problems

06-29-2009, 06:41 PM
Ok...The old lady's blazer is acting up...4.3 v6 all new ignition parts except the coil, new egr, injectors flushed clean, and it is popping (kinda like a lean misfire) under hard acceleration at mid to high rpm 4000 to 5000 rpms...been out to the dealer twice (and 1500 bucks lighter) and still no solution.....anybody have any ideas?....if I cant figure it out...there's gonna be a couple of pics of a Cat D11 rolling over a 96 blazer posted soon...:mad:

06-29-2009, 06:47 PM
the earlier vortech's had injector nozzle issues, and no, the fuel injection flush will not cure the problem if it is the nozzles.

another issue common the the flat tappet cam version SBCs and 4.3 v6s is flattening cam lobes but that usually shows up as more than a "slight miss under acceleration"

06-29-2009, 06:59 PM
Could it possibly have anything to do with either the fuel pump or filter?

06-29-2009, 07:15 PM
could need an intake reseal as well not uncommon in those vortec v6 4.3's all that excess air leaking would cause that kinda condition done many of those in my experience

06-29-2009, 07:28 PM
The 96 (therabouts) and up have problems with the valves sticking open when they get hot. Like going uphill under hard acceleration.

dirka dave
06-29-2009, 09:50 PM
Pull it out and sell it to Zacman for his toyota....

06-30-2009, 05:19 AM
I appreciate the help everyone...I'm going to check for intake leaks...and put an indicator on the rockers to see if they are within specs...and by the way..if Zacman wants it for his Toyota..its his...I have a small block that I can bolt in (and maybe a big insurance policy for the old lad cuz she has a lead foot) and prefer over the v6...