Expert: Robert Summers - 4/17/2008

Question
Hi Robert.  I've been having the same problems with my Blazer for the last 5+ months.  The problem seems to be that it's dumping too much fuel, causing problems such as stalling, back firing, and hard restarting.  I've had 3 different shops looking at it and have changed just about every component in it.  Crank sensor, Cam sensor, Fuel pump, Fuel regulator, Electronic Ignition Module have all been changed; full tune-up, and PCM was flashed and still no one knows what's causing this problem.  Now they are telling me that I can change the Central port injectors, but no guarantee this will fix it either.  I'm hoping you've come across this problem before and have a new idea that will fix my car.

Answer
Hi Maureen... you don't say what year it is... i will assume that it is 4.3l v6 . these trucks had a problem with the lower intake gasket if it is new enough truck...or it could be as simple as a plugged cat converter.... let me know the year and i may be able to be a little more accurate....


Hi Maureen... i got your message as it being a 95... those 4.3 l engines have a known lower  intake gasket problem...if you have changed everything that is in your e mail.i would suggest that you look at the intake...because those vortec engines have an upper and lower intake gasket they will sometimes leak so the engine is sucking air where it's not supposed to...because it may be doing that it will cause the computer to read wrong wanting to richen up the fuel mixture
another possability could be fuel pressure.. put a gauge in the line and check... low fuel pressure will cause this as well...a quick check would be too pinch off vacum line to pressure regulator and see if truck runs better and fuel pressure goes up...if i had the truck i could be a little more accurate. these suggestions are a best guess based on the info you provided... i hope it is of some help...