Hay all,

I have a 2000 Blazer ZR2. The problem is when I give it half throttle it falls on its face, it still revs up but it has no power at all. And now and then it will not start.

I have checked the fuel pump, it has 60psi. 53psi at idle. I have also replaced the coil and complete tune up along with fuel system cleaner. It seamed to help a little but now it's getting worse.

 

Air Filter? lol start running around with a DMM and check all your sensors that deal with fuel/air MAP, TPS, check egr valve, check your PVC valve, MAF sensor, etc backprobe them with paper clips.

 

how do you backprobe? what am I looking for, the check engine lite?

 

Is everything in the intake duct work connected properly? Reason I ask is that you can get real poor performance if all of the air being drawn into the throttle body doesn't come through the MAF sensor (either due to the fresh air make up hose being disconnected at the back of the intake hat or the intake hat itself not properly sealed to the throttle body).

 

to back probe bend the paper clip so you have a point, now look at were the wires go into the back of the connection of the sensor, slide the paper clip into that rubber area following the wire (your not poking a new hole in the rubber just fallowing the one that the wire is going through) Until you meet resistence, now stop, if you push to hard (like reeming the thing in there) you could damage your connections. Now just find your reference wire, ground wire, and data wire (Ground will be no voltage, reference will be 5 V DC, and the data wire or signal wire will be between 0-5 v DC) after you find out which is which, look at the data or signal wire voltage. Take that voltage and compare it to say a repair manuels values.

 

yes, the intake is sealed. I think I'm going to try some more fuel system checks, if that doesn't work Ill try the back-probing. i was told to use a battery charger to give the fuel pump a little more power and see if that makes it start. When i check the fuel psi before it would still start, now i have to crank on it for 5 to 10 minutes and when it dose start its running worse.

 

Sounds like a plugged exhaust to me.

 

Well I figured it out!! Weak fuel pump, not Dead but definitely dieing.
But thanks for the advice anyways!