I was driving my Truck about 1/2 mile from home and then I got a flashing engine light as the engine because to faulter. Turned around to head back home and the engine pretty much recovered and the flashing engine light turned off. I pulled the code and its a pending P300. The freeze frame data shows bank 1 with short and long term trim way negative -33.59 and -32.81. The trim is pretty normal at idle now. I guess I need to take it for a drive and monitor the O2 sensors. I assume the O2 on Bank 1 would be the most likely cause but it could be wiring. It would take some time for long term trim to get to -32. I was very low on fuel earlier today and it was acting like it was starting to cut out. I stopped for fuel and did not notice any problems are the way home. Anybody have any suggestions.

 

Flashing engine light is bad news. Multiple misfire. Severe engine damage can occur if you continue to drive it like that. Could be due to running low on fuel or starving for fuel, maybe.

 

Definitely do some more trouble shooting before you drive it. When was its last tune up? Injector cleaning. Throttle body cleaning. PCV change. IMO start with the basics. Then dig deeper if you need to. BTW if your over 100K could be 02 sensors as well.

 

I drove it around while monitoring the trims and O2 and thing seems to have corrected itself. I almost ran it out of fuel so maybe some junk got into the rails. There was no flashing engine light and the pending code has cleared. I had a total engine rebuild about 10,000 miles but they would not have changed the O2 sensors. It could still be intermitten so I will drive it some more and then look at the trim values.

 

I assume you checked the oil level, etc.


P0300

 

FWIW, O2 sensors should be changed ~60K miles (Service manuals and the manufacturers recommended replacement) because they degrade in performance the longer they remain in service. Don't be deceived by the notion that "They aren't throwing a code; therefore, they're still good".