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Loss of power.

JOES89K5

JOES89K5

1/2 ton status
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Oct 17, 2008
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Hello Members while out today I experienced loss of power/acceleration then a backfire on my 89 Blazer 5.7. The truck stalled out and of course the check engine light came on. I was able to restart and drive about a mile when it started to stall. I let off the gas placed it in neutral and coasted. The truck idled and I drove it home slower than I usually drive just to get it home. Just previously before this occurred I was parked idling for about 30 minutes. During the past two weeks my idle would be good then it seems to be just hanging on to idle. I would have no problem accelerating. When I got home And while parked I hit the gas several times with no stalling or backfire. Any assistance would be helpful
 
What code?
Loss of fuel would produce a backfire and maybe throw a code.
 
I really don’t need this. It stumbled backfired then stalled. It hesitated one more time but did not backfire. I’m going to change that canister fuel filter. Check fuel flow after I remove old filter.
 
Fuel pump going bad maybe?
Yeah, check fuel first in this case.
Distributor cap too for broken button, carbon tracing etc.
After it gets dark, go out and look for arcing from spark plug wires, spark jumping between terminals etc.

But the fact it is intermittent sure sounds like fuel delivery.
That backfire sounds like it got lean suddenly.
 
Yes I need to get it done. Snow is coming next weekend and I have a plow for my own property. I changed the fuel pump about 10 years ago. I’m going to order up some parts. Fuel filter, pump, gas tank straps. I was going to have some new front steering components installed this week which might have to hold for the following week.
 
Pull the code. Worst case scenario, it will point you in the right direction. Best case scenario, it will tell you exactly what is wrong and save you a ton of time.
 
That was easy no codes. Just the 1-2 initial code no others.
 
So the check engine light just flashed while the miss fire/loss of power happened?
Hmm.
With that knowledge, maybe check all the harness connectors.

You know, my Dad's GMC truck had a problem that caused it to randomly shut off.
It turned out to be the ignition wire connectors in the steering column were loose.
They were aluminum instead of brass.
The blade connectors had lost all their ability to pinch down and grip the blades of the ignition switch.

Not neccesarily your problem.
But poke around and look for loose connections, it's easy and free.
 
I have another vehicle but stayed home today because my furnace was acting up. So between waiting for the furnace repair guy I had checked the codes. The truck starts and runs while parked like nothing happened but after I get furnace checked I’m going to change fuel filter , check wires and take it for a drive.
 
During fall I installed new cap/ rotor Accel brand. New spark plugs. The wires were changed out last year but I have another set also accel brand if need. I also had to change out IAC plug because one of connections broke while doing other repair work. Everything is original so it became brittle and cracked while removing it numerous times. Everything worked great after that.
 
Maybe that piece of rubber fuel line that is submerged in the gas tank to the fuel pump & sending unit is split or collapsing inside--seems to be a fairly common issue on these trucks with electric in-tank fuel pumps..
Sometimes filling the tank full "hides" the issue until the fuel level in the tank drops low enough to expose that hose to air..
 
Check the spark plug wires for burns from touching exhaust manifold etc. Is it possible that the distributor hold down bolt came loose and timing went off? I recommend using AC Delco cap, rotor, wires (pre-made), and plugs. Check all vacuum hoses for leaks, including the cruise control hoses.
 
Vote fuel pump issue, only code would be lean run codes. With the quality of our fuel(alcohol) 10 years on replacement pump is about right.
Hope you figure it out.
 
I got the fuel filter. The mechanic at the station said older Chevy and Gm vehicles the ground wires going from engine to body/ frame would loosen up or fall off and cause bad ground causing intermittent power to computer box. Then when it finds ground it powers up and that excess of fuel ignites. I’m still checking.
 
Update. I checked all wires. I tied up all plug wires away from exhaust. Any other power wires which appeared to be in contact with brackets or metal were checked and taped up. Did not find any loose grounds. I do have a sloppy ignition switch which I believe might be the problem. When you put key in it makes a ding then supposed to go off when ignition is turned on. Mine turns off if I wiggle the key while it’s running. I think the switch is bad and allows it to intermittently shut circuit off then on.
 
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