1996 Blazer, poor acceleration, poor gas mileage

[ldr1ff]

I have a 1996 Blazer with the W code 4.3L v6. It has 105,000 miles about on it. I have had a problem for the last few months and it has really bugged me as well as costed me more money then i need to spend at the gas pumps.

1st, i have a check engine light that keeps coming on. Keeps showing misfires on just about every cylinder. Multiple times. Did a complete tuneup,( plugs, wires, cap, rotor, pcv, fuel filter, air filter), but still hesitates really bad if i stomp on the gas from a dead stop. The engine will chug and misfire. Best way I can explain the bog is to think of a 1970's gm car or truck with a 4bl quadrajet. You stomp on it and go barely anywhere. I can even hear it popping if i hold my foot in the gas. I am getting about 10-12 mpg in the city and not much better hwy. I have a occastional smell of fuel in the passenger compartment. I cleaned the MAF sensor in the intake duct with throttlebody cleaner. Nothing seems to help.

Any ideas what I should look for?
Please help.
Gregg

[DetroitMuscle]

Check the ignition coil and/or module?

[LTBlazer97]

Originally Posted by ldr1ff

I have a 1996 Blazer with the W code 4.3L v6. It has 105,000 miles about on it. I have had a problem for the last few months and it has really bugged me as well as costed me more money then i need to spend at the gas pumps.

1st, i have a check engine light that keeps coming on. Keeps showing misfires on just about every cylinder. Multiple times. Did a complete tuneup,( plugs, wires, cap, rotor, pcv, fuel filter, air filter), but still hesitates really bad if i stomp on the gas from a dead stop. The engine will chug and misfire. Best way I can explain the bog is to think of a 1970's gm car or truck with a 4bl quadrajet. You stomp on it and go barely anywhere. I can even hear it popping if i hold my foot in the gas. I am getting about 10-12 mpg in the city and not much better hwy. I have a occastional smell of fuel in the passenger compartment. I cleaned the MAF sensor in the intake duct with throttlebody cleaner. Nothing seems to help.

Any ideas what I should look for?
Please help.
Gregg

Sounds like the same issue i had. Bad MAF. It just wont clean, get a loaner and see if it helps. I must have cleaned and tested my MAF 3 times and it still said it was good. It would work for a day than it would crap out again. I kept getting Service engine codes for the "Misfire" as well, not including bad MAF sensor, and MAF circuit bad. I replaced the same things you did and a whole lot more (CAT muffler MAP sensor). My buddy (who drives a blazer too) suggested i throw in his MAF and see if it was just bad, and sure enough it fixed it. The chugging is what got my attention. If you try to do a power brake does it pop, chug and glugg? If so i think its a Bad MAF sensor.

[ldr1ff]

I havent tried powerbraking the truck. Will try that tomorrow if I remember it. I know that if i am fully stopped, and i gun the gas, i can make it studder and pop (from the intake manifold(backfire?)), and bog terribly. If i floor the throttle at speed and it downshifts, it will bog somewhat also and it hesitates. I checked the tran fluid to see if it was slipping, but it was clean, smelled good, and was to the right level. Also it doesnt seem like it is a trans problem as it shifts positively in each gear.

Is there a way to test the MAF and the coil and ign. module like the other person had mentioned?

[ldr1ff]

the check engine came on with the following codes po300, po174, po101, po171. Also showed missfires: cyl 1 1222, cyl 2 1053, cyl 3 1181, cyl 4 1736, cyl 5 2282, cyl 6 4276.

[fam_mechanic]

Originally Posted by ldr1ff

I havent tried powerbraking the truck. Will try that tomorrow if I remember it. I know that if i am fully stopped, and i gun the gas, i can make it studder and pop (from the intake manifold(backfire?)), and bog terribly. If i floor the throttle at speed and it downshifts, it will bog somewhat also and it hesitates. I checked the tran fluid to see if it was slipping, but it was clean, smelled good, and was to the right level. Also it doesnt seem like it is a trans problem as it shifts positively in each gear.

Is there a way to test the MAF and the coil and ign. module like the other person had mentioned?

the autozone componet locator say that 95 blazers 4.3w dont have MAF only MAP

[rlith]

Originally Posted by fam_mechanic

the autozone componet locator say that 95 blazers 4.3w dont have MAF only MAP

Look in the 1st message, he has a 96

[ldr1ff]

I powerbraked the truck increasing the thottle to the point the tires were slipping. No knock, misfire, popping.

Also, for information, my 1996 does not have the corvette TPI looking intake system. It has a single plenum with a throttle body on the top center of it, just like the old tbi engines did in the early 90's. Just so you guys are thinking about the right engine.

[ldr1ff]

Well, I pulled the MAF sensor for the second time. It was absolutely filthy. Caked with black gumk, i assume is oil residue from my K&N air filter i pulled from the vehicle a couple of months ago. Surprised i am still having residue on the MAF wires. Anyways, I took it off and disassembled it. I dont think i did that last time. I think i just sprayed it through the screen last time. So, i took it all apart and used some q-tips sprayed with carb cleaner. The gunk came right off. Carefully wipe down any gunk left on the wires and gingerly wiped down the three wire leads that go across the center of the MAF. took my time and wiped them down a few times. Everyone that says they are very fragile is correct. Carefully blew out the whole thing. Reassembled it. Before installing it i cleaned the air temp sensor( I think that is what it is) just after the MAF. I also cleaned the gunk from the throttle body. and wiped it down with a rag soaked in carb clean. Made everything look nice and shiny again. Put everything back together. Put my foot to the floor when starting it the first time due to all the carb spray in the intake. Started right up, seemed to run smoother. Let it run for about 10 minutes. Pulled the truck out of the drive, dropped it into drive and punched it. It smoked the right rear tire. Something it had not done in like 3 years. Now I step on the gas and it jumps. From 20 mph, i jump on the gas, it downshifts like now, the whole front of the truck hops up and it actually takes off.

Now, hopefully it stays this way. We'll see in a few weeks after it has had a chance to run for a while.

[ldr1ff]

I am getting the following codes on my 1996 blazer, 4.3L w code engine. codes as follows:Po300, Po174, Po101, Po171. It also showed missfire #1 1222, #2 1053, #3 1181, #4 1736, #52282, & #6 4276 on the scanner.

Checked fuel pressure and getting 60psi with the engine off and it holds. replaced plugs, cap, rotor, wires, pvc filter, fuel filter, air filter, cleaned maf sensor.

Any ideas? I had a hesitation problem which went away with cleaning the MAF sensor. Still gets about 12-14 mpg. still runs a little rough at idle. scratching my head as to what to look at next.

[ldr1ff]

runs much better with the MAF sensor cleaned. Still only gets about 12mpg.