2001 Jimmy - trouble getting engine started and acceleration?

Get a stoich meter gauge and hook it up to the O2 sensor wire, etc. Then you'll be able to tell if it's running too rich or too lean. A way to check the MAF sensor is to just unplug it. If it runs better (although it will stumble a bit because it initializes a "limp home" mode), then try using some MAF cleaner or contact cleaner on the sensor itself. Or then replace with new. Check the TPS (throttle position sensor). Loosen it up and manually turn it back and forth to see if it helps smooth out the engine. If it does, then good chance it's bad. In a worse case the actual onboard computer is shot. To check O2 sensors, put a multimeter on them. Here's how.

Connect the voltmeter leads to the feedback wire and ground terminals on the O2 sensor.

Set the voltmeter dial or option to the millivolt option on your voltmeter.

Start your vehicle. Run it at idle until it warms up to normal operating temperature. Your oxygen sensor will not give you a proper reading unless you are running the vehicle at normal operating temperature.

Check the voltmeter. It should fluctuate and then settle at 150 millivolts. Rev the engine (or have an assistant rev the engine). The voltmeter reading should drop momentarily while the throttle opens. Then, as the throttle closes, the meter should read slightly higher than 150 millivolts. It should then return to the 150-millivolt reading.

It sounds like fuel or engine management.

You may need to go to a dealer - sorry!