99 sierra 2WD with 4.8 vortech. Just replaced Fuel pump and sender, ran good for day (about 250 kms then engine light came on and had to limp home, engine bogged had no power unless I put pedal to the mat, then it would take off like nothing wrong.
OBD code reader says Random misfire (PO300)
Ignition coil out of range (coil 8) PO358
Bank 2 oxy sensor 1 no activity and both back o 2 sensors, low voltage.
I have a sensor tester, although probably a cheap one. Off vehicle and tested with propane torch, all 4 sensors seem to test properly.

Any ideas? Murphys law, my truck is down and then today a wheel bearing fried in my MKZ, so I have to fix one or the other tonight or I'll be riding my bike to work tomorrow (motorcycle)

 

OK, got my car going, wasn't a wheel bearing after all. My dad suggested I should reset the computer on the truck by disconnecting the battery for a few minutes. Sound logical? Is this the same as erasing the codes with the OBD code scanner?

 

Removing the power from the battery is the same as deleting them with the scanner if the problem is not fixed, the light will just come on again.

P0300 code indicates a random or multiple misfire

Symptoms may include:

the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present

Possilbe causes :

Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer


P0358 Ignition Coil H Primary/Secondary Circuit Malfunction

It is possible that this code is causing the first one also. Check your ingnition Coil and replace if it is bad.

If you need help on testing it let me know

 

That is alot of remove and replace options if I take it into a local shop.

 

i bet you it is the coil

 

Would just number 8 coil cause all that havoc? The OBD says problem with primary/secondary, but also pin points coil #8. Sensors are $120 a piece, and I doubt 3 are gone **** up at once.

 

have you tested the coil?

I will send you a PM with a link to some information on how to test it.

 

Dredging up my old post. Replaced #8 coil, that did no good. I absolutely did not believe it was the O2 sensors, but finally broke down and bought the 3 the OBD reader said were not working. Fixed! I would never have thought these sensors would make the vehicle run so bad. And the sensors did respond to the blow torch test with my sensor tester, but I guess they were not triggering with proper resistance or maybe the right temperature.
My old truck lives on