vaccum leak???

[blazerls2000]

my blazer has no acceleration, when i put the pedal to the floor when im rolling about 50 the rpms will jack up and the speedometer wont move it has no acceleration. someone told me it might be a leaking vaccum. and also my ac will switch from the vents to the floor.

[MT-2500]

Originally Posted by blazerls2000

my blazer has no acceleration, when i put the pedal to the floor when im rolling about 50 the rpms will jack up and the speedometer wont move it has no acceleration. someone told me it might be a leaking vaccum. and also my ac will switch from the vents to the floor.

Ac vent to floor may be a engine vacuum to ac controls.
But other problem on no power may be engine running or plugged exhaust.

What is engine vacuum reading at idle and at 2 K RPM?

Got good fuel pressure and secondary ign?
Any check engine lights or codes?

What engine and what is mileage and any work done on it?

[blazerls2000]

its a 4.3 vortec with 139700 no work other than regular maintence that i know of and i was told my fuel sending unit and fuel pump may be starting to go so i dont know about the fuel pressure but if i slowly press the accelerator its gets up to speed quick just not when i put it to the floor

how do i go about checking my vaccum and where do i start???
and no lights on the dash at all it runs great just doesnt have the power that it should

[MT-2500]

Originally Posted by blazerls2000

its a 4.3 vortec with 139700 no work other than regular maintence that i know of and i was told my fuel sending unit and fuel pump may be starting to go so i dont know about the fuel pressure but if i slowly press the accelerator its gets up to speed quick just not when i put it to the floor

how do i go about checking my vaccum and where do i start???
and no lights on the dash at all it runs great just doesnt have the power that it should

Well better check out that fuel pump.
Run a fuel pressure test for up to par.

Get a vacuum gauge and hook it to engine intake vacuum.
The ac controls are hooked to engine vacuum by plastic and rubber lines and sometimes a vacuum ball.

[Chevy Nova]

What year? Your dash lights could be a sign of ignition switch problem. Are you sure your starting out in first gear? Try manually shifting through all gears starting with first then second and third. I for the longest time thought I had a problem with acceleration and found out my van was in 2nd gear. My blazer with bad ignition switch also had shifting problem. Check for indicator lights on shifter if there not lit also you may have an ignition switch problem.

1997 was problem year but I have a 96 and 95 seem to have problems too. Lots of different symptoms. Not always no start. I never had that problem. Others have dash light problem.

Sorry missed the fact when you were rolling at 50mph. Still dash light problem could be ignition switch