Okay, well I'm leaving for Florida on Friday, as many of you know.

This tank, my gas mileage has been horrible compared to other tanks. Right now I'm sitting a few ticks above a half tank and only at about 120 miles... normally at this point I'm getting near 200, and 250 in the summer.

About a week ago, I did a valve adjustment to get rid of my lifter tick. Ran smoothly after that, gas mileage dropped a tiny amount. I think I over tightened cylinder 1's valves a tiny bit and may have contributed to the tiyn loss in mileage.

Fast forward to last Saturday, I took the entire upper half of the intake manifold and throttle body out of the car for a good scrubbin. Put everything back together, connected everything, and the car ran beautifully after passing some carbon and carb cleaner through the cylinders.

My other thought would be brake drag since the pads are brand new and the car doesn't coast like it used to. But I cleaned and lubed the slider pins really good and everything looked great when I had the front brakes disassembled. The rear drums werent touched except to flush out the fluid and bleed the entire system.

Is there something I couldve screwed up to get this bad of mileage?

If nothing I did contributed to the loss of mileage, I'm going to blame it on the single digit weather, spinning the tires in the snow and stop and go driving.

How long does it take for the O2 sensor to heat up? My drives to work are only 5 miles and at low speed, so the car never really reaches operating temp before I get to work.

Hopefully its just something temporary because of all the cleaning I did. I don't have much time before I leave to go get parts because of the holidays so I may have to deal with the bad mileage until I get to Florida... then I can fix it there.

Thanks for all your help guys.

 

If you're worried about brake drag throw a jack under there and test to see if the wheels spin freely (which you already new lol). I'm guessing that once you make that long run your mileage is going to even out. Short 5 mile runs in the cold will run you at high idle the whole way so it's not a very even sample for fuel economy in my opinion.

 

I agree with you 100% on both. Ill jack the car up tonight and spin the wheels. The pads were a tight squeeze to get in and out (had to use a hammer), so maybe they're not sliding well.

I plan on just driving down there and hoping it evens out... if it doesn't I'm bringing enough tools to work on the car, so I can replace pretty much anything.

I honestly don't think it's engine related. It runs smoothly, no surging idle, no stumbling, no loss in power.

PS - It's good to see you hanging out on HAF again!

 

I'm going to go read my CEL code... should be the good ol P0420 since it took a while to trip the code.

 

a CEL code for a faulty O2 sure wouldn't be doing you any favors on fuel economy lol.

 

Yeah, I know. But the engine would've thrown the CEL for the O2 much sooner than 2 days of driving. I've had the P0420 Catalyst System Below Efficiency for a long time, I just havent gotten around to replacing the secondary O2 because I know my cat is fine.

I went to Checker (now O'Reillys) to borrow a scanner and apparently they dont loan them out under the new management. I'll pull the code Friday morning before I go at AutoZone then... and bring my spare O2 on the road with me.

 

You did a lot of cleaning work on the intake manifold. Is it possible you disturbed the fuel rail-injector connections? These connectionscan leak significant gas. It may be difficult to spot as the gas evaporates quickly w/ a warm engine. You may be able to smell a leak.

good luck

 

I'll smell for gas and charge the pump a few times.

I doubt I disturbed the seat for them since I didn't work too close to them, I did unclip the harness to move it out of the way, but never actually disconnected anything on the injectors. I thought I would have to remove the rail and injectors to clean the EGR ports,like the F22, but thats not the case on the F23, it only has one EGR port on the passenger side of the intake manifold.

 

And I agree its good to see your name back here...

Angelo

 

A little update: I was at 112 miles and the fuel gauge a few ticks above 1/2... drove it to my moms for Christmas last night on the highway... managed to get to 185 miles as of now and still a tick above 1/2. Looks like the problem was in my head or the gauge was just being quirky.... Off to Florida I go! Smooth sailing! (hopefully)