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I remember replacing the bank 2 sensor around 20k miles ago however for the bank 1 sensor i have not and has about 60k id say (this side does not have misfires). One thing i did notice is how they are different in size being 2 different brands. The bank 1 sensor was a Delphi and the bank 2 that i had replaced was a Denso. Like i said before i swapped both of them to see if the problems changed and nope, the short term on bank 2 sensors are both 99.2%. Would if ever be worth to diy clean the injectors to get that out of the equation also? For some reason i have a feeling the injectors are dirty but how could the problem be intermittent then, how does the truck start fine all the time? Idk thats why its so hard to diagnose this lol.
Last edited by Jacob11531; March 3rd, 2020 at 9:37 PM.
I just looked up both O2 sensors on Rockauto.com to see if the numbers printed on your sensors matched the part numbers for new Denso or Delphi sensors. They don't. (I was hoping to see that the O2 sensors that were installed were not the correct part number - that someone either sold you the wrong parts or someone other than you installed the wrong parts.) What I did learn is that the upstream and downstream O2 sensors are the same. So, my first thought is to swap the upstream sensors on each side with the downstream ones and see what happens to the fuel trim values. If the values stay with the sensor, then you know one or more sensors has gone bad.
As far as cleaning the fuel injectors goes, I don't know how to clean them off vehicle. On vehicle, I would pour in two 20 ounce bottles of Techron Complete Fuel System Cleaner into your gas tank, fill up with some Top Tier gas and drive the injectors clean. If you have an AutoZone nearby, they sell a 32 Ounce bottle of Techron Complete for about $17.00 if you can't find the 12 or 20 ounce bottles on sale you have an option. That way the gasoline in your tank will be loaded with PEA which is a fantastic fuel injector cleaner and it won't damage any seals or sensors.
Right now I will be honest with you and let you know that I am running out of ideas as to what is going on and what to check next.
As usual, good luck and hopefully we'll persevere enough and stumble upon the solution.
At this point I would say just get some new o2 sensors (make sure they are the same brand) then I hate to say this but if that dont fix it get a new fuel injector
Ok i am just about to swap the o2 sensors right now but i also want to say that coil packs and wires should not be the issue. When i last gapped and moved the coil packs and wires i tried to follow misfires but even swapping the coil pack then the wire this morning the misfire stayed in the same location. Lately the misfires have been cyl 1, 4, 6, and 8. Cylinder 1 i swapped the wire and coil pack at separate times and thats how i came to the conclusion those are not bad. I think when i swapped the 2 downstream sensors the 2,4,6,8 misfires turned into 1,4,6,8 but im not positive, its been a while. I will update tonight what the 02 sensors do. I think this weekend if i dont get it resolved i will just give up on it lol. I need to just move on, there has been so much i have put aside for this thing.
I was diagnosing the same issue when i replaced the 02 sensor with the wrong one they gave me but ill still get the correct delphi
Thanks!
EDIT: Just moved the sensors from upstream to downstream in a cross pattern. I noticed the upstream sensors to be unlabeled and idk the brand, the downstream sensors were the denso and delphi (will buy another delphi to match) I could buy all 4 but for $200 but thats gonna be a couple more days. Truck doesn't run any different but the short term fuel trims for bank 2 sensor 2 and bank 1 sensor 2 are still a constant 99.2% (maybe a wiring problem or a scanner problem). I will update if misfires chance cylinder wise tomorrow when problem occurs. If nothing further from that, i give u lol and thatl be a wrap for this.
Last edited by Jacob11531; March 5th, 2020 at 7:21 PM.
OK on moving the 02 sensors. Just curious, what is your calculated gas mileage?
If you are willing to wait for parts for a handful of days, you can save about 50% on the 02 sensors by ordering them from rockauto.com. You get the same parts as what you would get at AutoZone/O'Reilly/Advance/NAPA/Carquest, just without all the markup.
I will update on the mpg in a couple hours. On my drive to work this morning i ran an engine light with code P0420 which pretty much says the downstream sensor i moved to upstream has sent a fault code. Pretty much 4 new o2 sensors and this was the problem all along I believe.
I will definitely order 4 from RockAuto to save money, cant beat the price. What brand would be recommended? Bosch run at $33, Denso has 2 part numbers both for up and down $36 or $40, ACDelco $40
I would stay away from the Bosch O2 sensors - I've read on other forums that they are not the sensors they used to be. I've put Denso O2 sensors on all my vehicles with great success, so I am going to recommend the Densos to you. I looked up the part number for your '03 and found that the most current recommendation is the 234-4651 (or 2344651). The 234-4407 is being phased out and is replaced by the 234-4651.
March 3rd, 2020, 9:35 PM
