Hello all! My husband and I have a 2002 Chevy Blazer 4wd that we are having continual issues with. We have an issue with total power loss when applying gas. The engine bogs down and then cuts out. We originally threw an error code of P0300, and have replaced both O2 sensors, spark plugs and wires, alternator, heated ignition coil and control module, fuel filter and fuel pump. However, none of this has completely fixed the issue. The truck is running better now, but still has the same issue. Please help!!!

 

We need some more info. When you say cuts out do you meen shuts down with all the start up lights coming on and you start it right back up. Do any lights come on when it's starting to bog before it dies like abs or airbag, Does it have the random misfire light still on or back on.

Try to think of every thing that happens and the order that they happen. Try to be as detailed as you can.

And for now stop buying new parts.

 

The spider injector could be leaking, its the most common thing that fails next to having 4x4 issues. You can have this tested by doing a fuel pressure test and leakdown. It should go up to 60-70psi, and not drop below 50 after at least 10 min. Its usually the regulator that leaks on the back of the injector, but dont just replace the regulator. Dont go cheap on this or it will bite you in the a$$. That's only IF its leaking. Taking off the upper intake will tell you for sure. There should be NO fuel under there, it should look black and dirty. Clean spots indicate fuel leaks.

 

I tried to drive the truck this weekend and here is how it performed.

When starting the engine, there seems to be no problem. The motor runs clean and doesn't spit or sputter. I am able to drive it at very low rpm and the transmission will shift. As the engine gets hotter, the performance gets worse. There is a tremendous amount of hesitation the longer the truck runs. Reverse is less functional than drive. I can push the gas pedal completely to the floor once it starts hesitating, and the engine will shake, and begin to stall. If I remove the pressure on the gas, the engine seems to recover, although does not run as well as when first started. Sometimes it will shut down completely, depending on how many times I've tried to push it and have it recover.

The check engine light remained on for the entire time. It was reset after installing the oxygen sensors, but came back on within a short time. I can't drive it far enough to have it evaluated, so I am not sure if it is throwing a new code now or not.

I appreciate all the help! Thanks.

 

Ok well its kind of tough with the spot your in right now. Autozone might let a code reader and pressure tester out the door with a deposit. Really depends who you get behind the counter.

It kind of sounds like a clogged cat. The quik way is to run the car hard at night and see if its glowing. I don't know if it will do it by just letting it sit at idle.

Another way is to pull one of the pre cat o2's and see if she runs any better.

Any rotten egg smell from the tailpipe?

You might try disconnecting the mas air flow sensor. if it runs bettter with that it can be cleaned with some maf cleaner from the parts store.

Anybody else with in the driveway tests?

 

So it idles fine, but dies under load?

They didn't still have map sensors on them by '02, did they?

Without codes it's more difficult, but I would check the throttle position sensor. Easy enough to check with a volt meter if a code scanner isn't around.