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.