Hi Guys im New here, but i have a slight problem.

I have a 96 Blazer 2WD 4.3L Vortec, I just did Plugs,Wires,Cap,Rotor Button,Fuel Filter,MAP Sensor, and a Mass Air Flow......the reason why i did this tune up is because when you push the gas slowly the car will sputter a little and then come out of it, but when you go to go up a hill or to pass someone, or even just to speed up the blazer dosent have any nut to get out of its own way, Any ideas why its doing this? It also has a brand new 260 dollar fuel pump

When the Blazer is running at idle the fuel pressure bounces around 50-52, With the key just turned on the on position the pressure is at 60, And with the key off the fuel pressure stays at 50 and then slowly climbs its way to 60, I have been told all these fuel pressures are fine.....

Help me please

 

air filter? clogged Catalytic converters maybe. bad gas? clogged TBI injector? I'd go with the catalytic. is the the exhaust makin any poppin noises. if it is clogged it is just like stickin bananas in the tail pipe.

 

I'm going with an EGR that needs cleaning, but a plugged cat is a possibility.

 

He says it's a Vortec, so no TBI. However, those fuel pressures sound low - I think the spec is closer to 65 psi for a '96. It is possible that the fuel pressure regulator has gone bad.

But do you have a rotten egg smell from your exhaust? If you do, the cat could be bad.

 

there is no way it could be the cat because i have a punched out one on it, its not the air filter because it has a cold air intake.

 

Then the next step is to pull the Vortec cover on top of the motor (2 T-30 bolts), disconnect the electrical connector to the IMTV (round thing in the middle- with 2 smaller Torx screws), unscrew it and gently remove it by twisting side to side until it comes free - you might have to spray a little WD-40 around the outside. Be careful with it; it has an O-ring that you need to reuse. When you reinstall, lightly coat the O-ring with engine oil.

Then look in the hole with a flashlight at both sides of the intake - if you see any gold-colored spots (in other words, not everything is covered in black gook), you have a leak. If on the passenger side, it's the fuel pressure regulator. If the driver's side, it's the nut kit (fuel pressure and return lines).

 

If the fuel pressure readings are correct as he reported them, I see no problem that would indicate a bad fuel pump or FPR. If the the FPR is bad, the pressure would drop when the key is turned to the 'off' position, not rise.

 

Fuel does not seem to be the problem. If the pressure were to drop on acceleration, then I would say that there is a supply problem.

I would lean towards a clogged EGR valve as well for the idle problem, but the no power while passing may be something different.

As stated, typically a clogged catalytic converter will cause your exhaust to smell like rotten eggs. To diagnose, you can remove the O2 sensor directly ahead of the catalytic converter. Be forewarned that it will be loud! If the truck runs better, then the catalytic converter is clogged and will need to be replaced. If you have a "punched out one", then you can scratch that. I do not know what the fascination of hollowing out a catalytic converter is, but to each his own..

Being a 96, this is the SCFI motor. What you are describing is the intake of a CPI motor. And I agree with Rich, the pressure would bleed down if there were a leak at the FPR or anywhere in the system for that matter.

Dirty injectors may be a contributor as well as a possible presence of water in the fuel. I would dump a bottle of ISO Heat into the tank at the next fill up. If you do not go through fuel all that fast, combine that with a bottle of Chevron Techron Fuel System Treatment Plus to really shock the system.

 

could it be the spark knock sensor? i read about them in my book, they retard or accelerate the spark timing a little under load or stress. Just brainstorming

 

any "pinging" with it ??

I'm still chasing a similair problem on my "96 TBI,but I get an awful amount of pinging under load on top of it not having enough "umph" to get out of its own way