I have a 96 blazer 4.3 V6 4x4. I am having problems with the truck bogging down. I took it to the shop because the check engine light was on and the codes that came up were mass airflow sensor and random miss fire and to far away. I changed the mass airflow sensor with 2 different used ones, and the code still came up and it still bogged down. I then went and got it it scanned againg and the same codes came up so i bought a new mass air flow sensor and the check engine light was still on so i unplugged it and it runs better with the mass air flow sensor unplugged. I wanted to say that my CAT is bad I think when I start the truck up it pins really loud and sounds like something broke off in there. Is there a chance that could be it ? so many people have given me ideas as spark plugs which i have changed EGR which i have changed. I am tired of spending tons of money especially to get it diagnosed .

Please help me if you can.

 

Wow. Yeah same thing here. I just replaced my MAF two days ago when my truck was giving me SES and MAF codes. Thought it would be an easy fix. The new one has done nothing different.

My truck actually will rev up to about 3k just fine ( I have a manual ) and then if I keep the accelerator where it is, it bogs down quickly just after 3k until I let up my foot.
It has to be something else and it throwing faulty codes. Mine is an '04 and I do need to replace wires, plugs, cap and what not for regular service maintenance but I dont think that is going to rectify the problem.

Do you know what the pin out is for that connector? I thought maybe the wires were broken/disconnected or something like that. I would assume they are maybe 12V, reference voltage (0V/GND), and output but I am not sure.

 

If replacement with a known working sensor results in no change in the condition, but running with it unplugged results in a change, you really need to start looking into the wiring and digging deeper with a scan tool looking at the actual sensor data to determine the cause. The days just throwing parts at a problem are really gone. The problem needs to be troubleshooted using the trouble code diagnostic charts that are available to solve the problem properly and efficiently.

 

I went to this website HOW TO TEST IGNITION CONTROL MODULES and MASS AIR FLOW SENSORS and MORE. Easy, simple and fast test articles! it has really good information. I will try it but if i do find a wireing problem how do i fix it? swartlkk I Also could the muffler be blocking it? Or is that out of the question ? Whyy would it run better unplugged is it because it is running off of a different sensor?

 

Dont mean to revive a dead thread, just providing an answer for future questions.

Unplugging the MAF, will cause the PCM to say "OK, we're no longer getting any input from this sensor, let's go with a generic setting from that sensor"

This will cause the PCM to send signal(s) to the other sensors, basing the fuel metering on 'defaulted' MAF settings that are hardwired into the PCM.

-OSS

 

^^ Otherwise known as forcing it to stay in "open loop"