P0452 Chevrolet -

Question

My blazer seems to deviate in rpms from 600 to 550
While running in drive with the ac on and I previously had a code of p0440 of which the gmc dealer installed a vent selenoid then came up with code p0452 cleared that and said it was ok.
Had the fuel injectors, & throttle body cleaned.
Repaired a vacuum leak but it still seems to deviate in rpms and run rough with no codes according to the dealer mechanic of whom has worked on a lot of these chevy blazers 4.3ltr engine.
Any ideas?
I'M RUNNING OUT OF PATIENCE.

Answer 1

These trucks are known for this symptoms they nicknamed these the spider fuel injector which are known to internally leak, and if that is not it the fuel pressure regulator are also known to leak, check the oil condition, by smelling it for raw fuel, other than that you would need to do a fuel volume test.