Why does my engine have low power it will not accelerate?

Should be 5 volts to the maf .Have you checked plugs wires/spark plug boots etc yet?Any codes in the computer?

No codes and we checked all the obvious things. When I asked this question I had a clue but wanted some confirmation... I spent much of the day on Mitchell-on-demand and AllData... here's what I figured out (but won't be able to confirm until tomorrow)... It is a combo MAF/IAT with 5 wires. One 12V and an input wire for the ECM (IAT), and three for the MAF, a ground, a 5V, and another input for the ECM. We had no 5V signal, in fact that wire was grounded...until we unplugged the ECM. When we tried manually applying 5V, we popped the 15A ECM fuse (didn't see that at first)...So, tomorrow we cut the "gray" 5V signal wire at the ECM, apply 5V from one of the other lines (such as the MAP) and see what happens. We might be able to cheat the system, but my diagnosis is a bad ECM!
I asked this question on justanswer.com a few days ago and they were all clueless until today when I hinted at the answer. I wish someone would have steered me in the direction on how to check a MAF in the first place!

Yeah if you unplugged the ecm and the 5v reference wire was no longer grounded sounds like a bad ecm.You really can't cheat that maybe get a used ecm?Is your car a automatic or manual transmission?

Automatic. I'll find out today about "cheating " the system. Theoretically, if all I need is to get 5V to my MAF, my throttle response might be resumed... odds are that that isn't the ONLY problem with the ECM!
I was sooooo close to buying a new MAF (after having purchased a TPS); this was a big lesson for me!

Sometimes there is multiple failures in the ecms othertimes jus one.But when they start failing best to just replace them.

One last question- I've ordered the replacement ECM (the only reason I was considering the 5V jumper wire was to confirm my diagnosis, but then I thought, why?)
Will I have to have the new (used) ECM flashed on this particular vehicle?
Thanks

I would say to give a honest answer on the reflashing on the used ecm.From what I have seen/experienced usually it all depends on how the options from your car differ from the donor car.For instance abs cruise control etc.Those little things can cause issues.

the car acts like it does not want to pick up. when I give it gas it sputters. if I back off the gas it kind of picks up. he has replaced the o2 sensor, the temperature senors, and an idle sensors. but we could not find the other sensors? what could be wrong? and where can we find all the sensors?

I don't want to be rude but did you replace the spark plugs? If not I would start there it sound like its misfiring.

Here is a guide to help

https://www.2carpros.com/articles/how-to-change-spark-plugs

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Let me know what happens.

Cheers, Ken