Okay,
I know this has been covered by so many people it's crazy. But after searching every thread I find no one every gave a solution or answer on how to fix.
Details:
I bought this 1996 Chevy S-10 Blazer maybe a week ago, When i first started it ran and drove great! Had a little stutter around 1,000-1,300 Rpm so I assumed it needs a tune up no big deal. Other than that revved great and etc. Well I payed the owner and drove away. I noticed the truck getting to the operating temperature like it should. Well when this truck warmed up the problem was there. It was bogging,Misfiring,jerking but if i eased into the throttle and kept it there it did all right but anything past 1/4 Throttle the Misfiring would get worst. Well I got the blazer home, Went out after it cooled down.... What do you know started back up ran and drove pretty decent till it warmed up and the problem was still there.
BUT IF I UNPLUG THE MASS AIR FLOW SENSOR THE BLAZER RUNS NEAR PERFECT ALL DAY LONG!!!! The truck was throwing codes for bank 1 and 2 Running lean. But that was because of the misfiring.

PROBLEM:The Blazer Misfires and bogs after the truck is warmed up at operation temperature.

PARTS I HAVE TRIED AND STILL NO FIX:
Brand New Mass Air Flow Sensor & Cleaned Air Intake Plus new filter
The Cat is not stopped up
Fuel Pump is great Holds 60 psi while running
Fuel Filter
OTHER PARTS PEOPLE SAID I NEED TO TRY:
Temperature control sensor for the Ecm & Not the Temperature Gauge sensor
The coil since the problem happens when warmed up

SO ANY HELP WOULD BE GREAT!!!!!!

 

"The truck was throwing codes for bank 1 and 2 Running lean. But that was because of the misfiring."

Might be the other way around... the DTC's were causing the misfire

What were the exact DTC's, (Diagnostic Trouble Codes)?

When the engine is first started, the PCM, (Powertrain Control Module) operates in open loop. During open loop, fuel mixture and ignition timing is calculated with data from the TPS, MAP, MAF, & ECT sensors, and oxygen sensor data is ignored. When the coolant reaches a specified temperature, or the engine has been running for a certain amount of time AND the coolant temperature reaches temperature, the PCM switches to closed loop operation. In closed loop the PCM primarily uses oxygen sensor data for calculating the fuel mixture. Oxygen sensors produce voltage: A rich mixture produces above .4 volts, and a lean mixture below .4 volts. The sensors ability to produce sufficient and accurate voltage output deteriorates with miles.** If the output voltage is low, (lean) when the PCM switches to closed loop, you will instantly end up with a misfire, hesitation, reduced power, poor fuel mileage etc etc. Your oxygen sensor DTC's pretty much confirm this. AC Delco, Delphi and Denso sensors have a noticeably faster response time than other oxygen sensor manufacturers.... something to keep in mind when shopping

** At ~100K miles they have deteriorated enough to make a substantial difference in engine performance. This is why they recommend replacing them at 100K.

 

Okay, I just replaced both Oxygen sensors (AC Delco) Still have the same problem. Let me explain it again. Like mentioned above, Once the truck is warm this missing and etc will happen. But while it's still warm I can shut off the truck and restart it. The truck will run fine for 5- seconds and the same problem is still there. Also I did reset the check engine lights with a scanner.

 

From post #2: "When the coolant reaches a specified temperature, or the engine has been running for a certain amount of time AND the coolant reaches temperature, the PCM switches to closed loop operation."

On a warm re-start, the PCM will switch to closed loop very quickly, 5 seconds is not out of the realm of possibilities.

Also from post #2: "What were the exact DTC's, (Diagnostic Trouble Codes)?"
DTC's never say a part needs replacement, it tells what circuit the PCM detected a problem in. The flow chart must be followed to determine what the problem is. It could be there's a broken wire or a bad ground in the oxygen sensor circuits.