I live in a rather dry/hot climate, there are hills, but the freeways are mostly flat. I don't really do any hauling (I am considering getting a couple bags of cement to throw in the bed and hopefully smooth the ride out a bit), and I have been driving it very easy lately because I have yet to fix the wild vents issue and like to have my AC in this summer heat.

Also, I am using 265/75/16 tires with 3.55 gears.

 

Lotta similarities in our trucks. Though, mine is a 2500..... The Hot weather may be a contributor, but, not like there is anything you can do about that..... Move north?

What pressure you running your tires at? Get any uneven wear?

Seems like you have done pretty much everything that I would suggest already...... and you *should* be able to do better....... but, as I said, the heat may be the factor that you can't do anything about......

 

I was getting some uneven wear on the front passenger side tire, but that was because of a bad wheel bearing, which I have since fixed. After that I rotated it to the rear to square it up a bit, I am getting close to wanting to rotate again, but that should really not be too much an issue.

Also, I've been doing a bit a reading around on this and I was seeing a few other potential issues. Could it perhaps be a bad MAP or TPS sensor? How would I go about checking if those are bad? What about an exhaust leak before the O2 sensor? How would I check for an exhaust leak? My brother and I were able to find an exhaust leak on his Jeep by running Seafoam down it and lying under it while revving the engine, not sure if that is ideal though.

Thoughts?

 

Exhaust leak you should be able to hear.... although, I have poured a bit of oil down the intake (engine running) to see where the smoke came from.....

TPS you can test with a meter. Analog works best. The digital guys just aren't well suited to the task. Resistance across the pins should change smoothly, with no flat spots, and no jumping around. If it does, it's bad.

MAP sensor? No idea...... Probably put a mechanical gauge on it, and a scanner, and compare readings at various throttle openings....

 

I guess I'd have to get an analog multimeter to test that then... It seems like it may be worth it to replace the sensors and see if anything improves.

Also, what about the IAC, could that be contributing to the mileage issue?

 

one thing i noticed about Bosch parts, from my experiences anyways, they've been problematic. Bosch seems to perform better in foerign cars, or higher performance engines that require higher octane fuel. Id go back to stock NGK plugs and just see if theres a difference in MPG. dont use those stupid E3 diamond fires eathier, its just an advertisement scheme. I had them in a ford truck of mine, ran horrible, went back to motorcraft plugs, night and day difference.

 

As I mentioned, I'm not sure exactly what plugs I purchased, but I believe they were the cheap Bosch ones at AutoZone. The thing is, I think that I would have noticed the performance loss from switching to the Bosch plugs had there been one, that is unless the previous plugs were so bad that there was an actual improvement. I could try replacing the plugs but it feels like it would be a waste of money considering there are only about 20k miles on these plugs.

 

you dont have to change em now, maybe give them a little longer, or pull them and re-check the gap. i was just giving my 2 cents of my experiences with Bosch parts. the only bosch parts that i use that i know work good are O2 sensors.

 

Just swapping out parts in hopes of fixing something is rarely a good plan. Unless you have money to burn, test first, replace those that are bad. If the engine idles the way it is supposed to, IAC is fine.

 

years ago my brother and I had matching 97 dodge ram sports 4x4s his was 5.9 mine was the 5.2.. one weekend we decide to help each other do full tuneups on our trucks
2 weeks later we were BOTH bitching about 1-1.5MPG loss in fuel mileage


did a lot of reading as mostly everyone had the 2nd gens and the sites were on fire with activity.. long story short the consensus was the bosch plugs were NO GOOD for our ignition systems and it was recommended that we switch back to the autolite 3924s...


we did and the mileage came back with the switch




just putting it out there