That's a good point. I think I saw a reference to a 275, that might have been for the 15" wheel. Can't recall, too many years, too many beers.
I apologize, I know we are getting off topic. Just maybe killing time until we hear what the shop has to say.
Frank
That makes sense. To get back to MPG's, bigger more aggressive tires definitely increase road load (more rolling resistance, wind resistance, mass, and inertia) but not to the tune of 8MPG. I could get 16 when my truck was stock and I gave up 2-3MPG most of that being tires but the roof rack...
So, I like many have 4.88's and 35's. I find I am about 9% undergeared with some wear on my tires. Soooooo yeah, I go less far than indicated so MPG's are actually worse but no where near 8MPG. If I am easy on it I can still get 14 on the highway. I am rarely easy on it though.
Frank
Makes sense. I usually fix my own stuff but kid #4 came along when my engine needed rebuilding and I punted.
Owning old trucks seems to present us with two paths, we learn the trucks and trade our time for money, or we pay someone else and do the same in the other direction.
If this shop...
Yes, a few possibilities actually. It would be very helpful if you noted the Vf1 and Vf2 voltages. It's a starting point as to what the controller is trying to do. You will need good O2 sensors for those readings to mean anything though.
I really think you should check out that link I...
Can you see what the O2 voltages are, are they fluctuating? Also, can you see the Vf voltages? We really need a lot more information to solve this. There are a lot of potential causes.
Keep in mind a rich engine leads to cool exhaust which means cool O2 sensors which will fail to fluctuate...
I meant unplug the O2's not remove them entirely. It forces the engine to run open loop and can help to point to different sensors as being an issue or not.
What does the scan gauge report for those values?
Frank
So did you unplug the O2's and drive? Just want to make sure we understand the test. If you did we then need to look at the remaining sensors and see why the base injection duration is too long allowing for too much fuel (assuming you are sure you don't have a leak somewhere...).
Let's get...
I have that RPM issue from time to time. You might try this. Unplug the O2 sensors and repeat the drive. See if the MPG's change. Also, do you have an OBDII scanner? You can get them on Amazon and use an app like Torque on your phone to read the O2 values realtime. It can be indispensable...
Is it the same on all 4 wheels?
In that one picture it looks like you might want to run a slightly higher pressure. Typically balance, worn parts, or a bent rim would cause that cupping / scalloping, however, low pressure can cause the tread to squirm under load and also cause wear on the...
I couldn't agree more. I have this on my google drive set to access offline so it synchs to my phone, tablet, computer... etc.... It's the only way especially if you need it when out of cell range.
Frank