Okay, going to need to back pedal and go forward again.
Changed out the last O2 sensor that was on the truck. Found the last owner was true to his nature, and he used what looked like generic eBay parts. The sensor wasn’t branded and looked rather cheap. Installed the Denso sensor and that did in fact cure the bank ‘2’ too rich code from the system.
I ran a full check with a multimeter on the installed (also generic) TPS. It’s okay with no dead spots. Did put in the P&P IAC motor. Didn’t clean it up much. Just did a light coating of silicon on the sealing rings and blew some of the carbon off the valve.
Everything ran fine for about 15 minutes, and then we went back to square 1. Here’s what happens:
Random miss-fires occurring during either idle or just off idle driving. The other day it flagged cylinder #3. So, we picked up a couple of coil ‘packs’ (this uses coil over plug design) Installed and made no difference.
Then noticed something really unusual. I reset all the codes using my HT200 blue tooth reader. (it’s slow for the data stream, but for the price it does pretty decent for data). After tracking accessing the miss fire monitor system. ALL the miss fires are only occurring on bank 1. To some degree of severity all 4 cylinders on bank 1 just ‘out of the blue’ will start miss firing like wildfire! Bank 2 appears to be 100%. Sure, it still reports a pending code for a bad converter. (I ran the scope down. It’s got light carbon build up-but does not appear to be plugged) We tossed a can of the converter treatment into the gas tank. That monitor (yes it actually showed how bad it is) The converter is only about 10% over the threshold to flag the CEL. So, we’re hopeful the chemical cleaning agent can help restore it enough.
So, my quandary. What would cause this issue with the miss fires? Only on bank 1. And only at off idle or at idle. The truck drives 100% the rest of the time. (Once it’s driven for a short while the issue also vanishes)
Any help is appreciated. I’ve been tinkering with cars for going on 35 years. This one has me stumped. was thinking vacuum leak (gets hot and seals) But that would be more ‘whole engine’ effect and not just 1 entire bank of the engine.
S-