Started running poorly a few weeks back, replaced fuel filter because cheap & easy....ran great for about 2 days and then back to rough again, sputtering and sluggish when accelerating and uphill. Feels like a misfire sort of but when unplugging the maf sensor it ran much better for a drive cycle or 2 and then crappy again. So is there anything else I should check before buying a new maf sensor and starting the old game of throw parts at it till Im broke/it's fixed?

 

I'm not an expert on the MAF sensor, but an easy check to do is measure the fuel pressure at the test port immediately before the fuel line goes into the plenum.

There are several threads on how to do this and others here who can help if you can't find those old threads.

Once you check it, you'll be able to eliminate one possible cause or get pointed in the right direction regarding the system to check.

BTW, what year Blazer do you have?

 

It's a 97 2wd LS 4door
Up date new maf sensor and a few drive cycles and codes gone and fuel trim finally righted itself. Changing oil today with some badass lubrication engineers oil. She oughta be a smooth operator after that!

 

Excellent.

Be sure to ask any questions in the future.

 

Just couldn't leave well enough alone so I returned the maf sensor and ran like **** again after a few drive cycles. Put a new one on again and still running like crap but haven't driven a whole lot with it on yet, praying the thing will correct itself again this time and it isn't something more costly

 

We have some people on the forum who are really helpful with diagnosing problems so be sure to ask for help. Getting a good idea of what is going on can save a lot on parts!

 

Think I figured out what happened, in the process of driving with my old maf sensor I've since caused spark plug #5 to fail, I'm now throwing a cylinder 5 misfire. I went ahead and got a new maf sensor today and installed but I think the damage was already done. Will check plugs and cap and rotor tomorrow and report back

 

The dizzy on those go bad, can you hear it rubbing? Also, when mine could barely accelerate and got a code made me think it was MAF but turns our was the cat converter. The clue was a little rattling in there.

 

If you would like to properly diagnose this problem:

1. Any other codes?
2. What year is this truck?
3. Back probe the pwr and gnd wires at the maf sensor while plugged in and running and report the voltage
4. What is your maf reading at idle in g/sec
5. What is that value right before a full throttle 1-2 shift

George