Christian Steffen
I'm Awesome
Still looking for an answer. I cannot get the O2 sensors out. Purchased an O2 sensor socket and soaked the sensors in Kroil (penetrating fluid) to no avail. I don't want to ape on them and break them and end up in a massive world of hurt because I have no proof that these are the issue. Truck still fires up great and runs good cold. Sucks when I'm towing. I picked up my brother in law's tractor last night and towed it home (15 miles one way). Truck ran ok on the way out there empty and then slowly deteriorated on the drive home to the point I could barely get up to 50mph on the last leg of the journey. I've been reading up on anything I can find that deals with this hesitation/loss of power/crappy fuel mileage problem that seems to plague this engine and so far everyone who's solved their issue's solution is different from everyone else. What a gremlin factory.
Two new discoveries/possibilities that I am going to try tonight. My truck has had some witchcraft done to the battery cables and when the truck warms (or when the alternator has charged the battery back to full after starting) the voltage drops to below 14. I know that 13+ volts should still be plenty to run the truck but I'm going to check and improve grounding contacts, just to make sure. I'm also going to replace my Ignition coil. Its one of the few components that will deteriorate performance wise due to heat. Plus the issue has been getting progressively worse. I'm leaving on another long camping trip soon, but this time I'm pulling two mountain passes and will be driving in much hotter conditions, something this truck hates.
**** that sucks.. And the fact that you can't get above 50 pulling leads me to rethink the o2 sensor diagnosis. When the truck is in high throttle scenarios it will go into what is called power enrichment mode. It commands ~12.5 AFR and adds spark, so you should make a bunch of power. I believe the factory delay is 60 seconds for this, which is really ******. Pretty much everyone that tunes these removes that delay and makes it come in sooner.
The reason I doubt the o2 sensors are the issue now, is that they aren't used in high throttle areas.
Though looking back, I see you didn't have this issue until you replaced the thermostat?