poor gas mileage.

[jappelt]

Can anyone tell me what would rob me of my gas mileage after cleaning the MAF sensor, changing the air filter, cleaning the throttle body, replacing the fuel filter, gas cap, pcv valve, correct air pressure in tires and plugs and wires only have 20k miles on them and no CEL to check for codes. Right now it gets about 11 to 13 mpg in the city and 14 to 16 mpg on the highway. Can the transmission not shifting properly have this effect?

 

[koda2000]

running your A/C really brings down the MPG. during months i don't run it i get 17+ rural city and 23+ hwy. during recent really hot weather i was seeing 14'ish city and 20'ish hwy. you don't say which engine or what diff gear ratio you have, so living in Houston TX those MPG's might not be that far out of line. another thing that can adversely effect fuel economy is if your O2 sensors are reaching the end of their service life (120K or so).

 

[drdoom]

If you lose lockup your mileage will suffer greatly. And as Koda stated, O2 sensors can drop your mileage a good bit.

 

[bill06447]

You say you did a bunch of maintenance items, then mention the transmission not shifting properly. Was the transmission an issue prompting you to do the work? Or did it act up afterwards? Clarification might help narrow down a problem, if any. Also, which engine? 2wd .4wd. or AWD?

Bill

 

[koda2000]

If you lose lockup your mileage will suffer greatly. And as Koda stated, O2 sensors can drop your mileage a good bit.

true. i didn't see the comment about the transmission.

 

[jappelt]

Missing info.

The engine is the 4.0L SOHC, the transmission is 4x4 which just had a flush and fill with synthetic fluid about 2mo. ago but it hasn't been shifting right for about 6 to 8 months, seems to be only 1st thru 3rd. The rpm's reach 2500 before dropping to 2000 after the shift as to where it used to fall to 1500 plus there is a speed increase of about 5mph from what it used to be before shifting. Once it hits 4th gear everything's fine, proper rpm to speed ratio. I thought it might be an O2 sensor but that would have thrown a code, it's not throwing a code. I'm starting to think fuel injector but there no rough running or idling. Before I was getting 15 city 20 hwy. compared to 11 to 13 city and 14 to 16 hwy. Forgive my ignorance but I read somewhere that it could be electrical, is that possible?

 

[my98nnj]

Check the engine coolant temp sensor. Make sure it's within spec when it's up to operating temp.

 

[jremington59]

What did you use to clean the MAF sensor?

 

[jappelt]

CRC mass air flow cleaner

 

[bill06447]

There's a switch that unlocks the torque converter when the brake pedal is depressed-possibly out of adjustment or faulty? Not sure which one it is, possibly connected to the one affected by the recall?

Bill