Throwing P0121 code and getting 5.8 voltage at WOT isn't referance at 5?

What is the deal at idle it is 1.3

Gilbert

 

Which voltage?

Check the reference +5V against block, chassis
and some PCM connector reference ground. If
the grounds are apart then things will be messed
up, find the broken ground strap or loose strap
connection. If your 5V is not truly 5V out of the
PCM, then you're in for a new PCM I reckon
(hopefully an emissions-related warranty item).

 

I understood everything but the warranty part. Anyways I got it fixed before i had a chance to read your suggestion the grounds on the back of my driverside head weren't tight enough. I am seeing 4.79 now and the car doesn't sputter.

Gilbert

 

Well I spoke too soon car still sputters and backfires and my battery went dead. Car was running and all power went out. The battery puts out about 11 volts when I crank it and I increase throttle the battery goes down to 10.7-10.9. I am thinking the alternator might be going out. There isn't any codes. Would the alternator or battery not putting out 12 volts have anything to do with the sputtering and backfiring?

Gilbert