Gas mileage dropped after tune-up

[p_tr1ck]

Hey guys, a little while ago I did a suspension job and new wheels/tires on my truck. At that point I went from 275 miles per fill to about 245 due to the larger tires and heavier wheels.

So, recently I went for a tune-up to try and get some miles back. They did the fuel filter and pcv valve and some hoses, that's it. My range has now dropped to about 220 miles per fill.

Anyone know what's going on?

 

[99Runnr]

Tough to say. 10% worse over 14 gallons is like 1 mpg. That's pretty marginal.

Any different driving habits? Why not plugs and wires? Oil, diff fluids, ect can typically lead to some economy gain over a pcv swap. Are those in good order?

 

[etc.]

From what you said you had done, I will venture to say they routed a couple hoses (vacuum?) to the wrong locations.

How's it run?

How many gallons per fill up? Same amount of gallons as previous fill ups? Or does it vary?

Air intake secure and tight?

 

[p_tr1ck]

Thanks for the reply. Plugs and wires were done last year so those are still good. My wife works at a quick lube company so all fluids get done regularly. Air filter is brand new too.

 

[etc.]

Can you post a larger picture? I still have feeling in my index finger from scrolling.

 

[p_tr1ck]

From what you said you had done, I will venture to say they routed a couple hoses (vacuum?) to the wrong locations.

How's it run?

How many gallons per fill up? Same amount of gallons as previous fill ups? Or does it vary?

Air intake secure and tight?

Seems to be running the same as before. Same power, and everything seems smooth. I haven't checked to see if vacuum hoses are tight but I'll do that tomorrow.

 

[p_tr1ck]

Can you post a larger picture? I still have feeling in my index finger from scrolling.

Ha! Sorry, it looks normal on mine. I'm using Tapatalk on my tablet.

 

[etc.]

Seems to be running the same as before. Same power, and everything seems smooth. I haven't checked to see if vacuum hoses are tight but I'll do that tomorrow.

I would try to find a diagram of the vacuum hoses and use that as a reference.

 

[p_tr1ck]

I would try to find a diagram of the vacuum hoses and use that as a reference.

Thanks for the idea! I have a Haynes manual which should have a diagram

 

[St Runner]

I don't think anything that you say they did should really be called a tuneup. More like maintenance. Its possible they reset the computer and that changed the milage or has been stated they hooked some of the hoses incorrectly. A tuneup is plugs, wires, air filter (which you have done), clean the maf, and if it has been over 100,000 miles replace the front o2/af sensor.