Hi all,

I am getting the following codes during warm up: P0132,P1300,P0301,P0303,P305,P0307. Truck runs really rough and then clears out.
Occasionally the truck will also throw a P0430 and P0420.
Runs perfectly fine once up to temp. The ultragauge is showing the rear 02's to be reading very erratic voltage, and the fronts to be doing the same. I had a pretty bad valve cover leak on the left side of the engine which I have just repaired. What do you all think the next step should be? O2's have been replaced in the past 2 years and I also new aftermarket cats.

 

Any work done recently? Very unusual for all the misses to be on one side. Very hard for bad 02 to cause this, there is a limit to how much it will influence fueling. Everything on one side means unlikely it is coils or wires, most likely a vacuum leak on that side. Loose manifold bolts or bad injector o-rings.

 

Nothing done recently, its been super reliable up until now. My only question is why would it run fine once warmed up?

 

Maybe the O2 heater power has shorted to the signal wire. Then when up to temp, heater is turned off. Just brainstorming without reviewing the wiring diagram or logic, for what it's worth. Solve the P0132 code and the rest will likely follow.

 

Thermal expansion could be reducing or eliminating whatever is causing the vacuum leak.

 

Bringing it to a shop this weekend to have them take a look. Thanks for your help guys. I will report back.

 

Replace the Bank 1 O2 sensor.

Or, if you want to confirm the diagnosis, swap the upstream sensors side-to-side and see if the faults move.

It was once gospel on this forum that a failed O2 sensor could not cause misfires.

That's since been disproven by several here, including my personal experience with my truck.

The only engine management component shared by, and exclusive to, either of the two banks of cylinders is the upstream O2 sensor.

 

Just got the truck back and running great.
Problems solved as listed:
-Coil Packs were cracked and bad on both sides. - replaced.
-Plug wires were worn and arcing. - replaced all plug wires and spark plugs
-02 sensor and heater circuit - replaced bank 1 sensor 1 and heater circuit.
- compression was checked. - all above 105 psi.
- intake manifold gasket was broken.
- unrelated but front left wheel bearing was shot. - replaced.

 

That’s good news, although I think 105 psi compression isn’t very good.

 

Its old and original, still runs and drives fine. So I am not concerned, also not sure if the shop did the test correctly by keeping the throttle open. I might do another test on my own time.
No cylinder had a compression less than 15% of the other. All were between 115-120, which makes me think its likely the test was done incorrectly, unless something is really wrong with my motor.