ZR8ED

How about something less obvious? Wheel bearings? Have they been checked and at a minimum repacked with fresh grease?
Tires? Wide sticky tires = more grip. More grip= reduced mileage. Poorly inflated tires can kill mileage too. How about transaxle oil? fresh? Driving with the headlights on all the time? Lots of drag there too.
One percent here and one percent there can add up fast.

Oh one last one...your right foot is a major player when it comes to fuel mileage.

River

Check, check. Checkity check. Right foot was under strict control for 95% of this tank. Kept it under 2k when on the highway, and I drive like you're supposed to; pay attention and stay off your brake.

What else!? I'm gunna try to find a wideband tester too.

This sucks! Lol

Hollywood D

Do you do a lot of rush hour driving? Stop and go kills mileage horrendously.

ilikemy944

Also what speed are you cruising at?
The auto tranny puts the revs pretty high at normal highway speed...
19/29 is for the manual I think - what are the factory specs for the auto? I imagine it will be way less.

ilikemy944

Auto 17/22 - from EPA

River

Sticker from the 88 window: 19 city 29 highway.

Talked to a bunch of other automatic owners. Seems the consensus is a low low low of 17, and a high of 30+. If you can do it (and it's tough to do), keeping the rpm's low (under 2k) around 50 mph-55mph will be the sweet spot of scoring the 28-30+.

I don't really get stuck in rush hour, and plan my routes accordingly. I drive like how you should (never ride the brake, look far enough ahead to react and coast to a stop or coast far enough back to not use the brake or stop). Only floor to pass, 50-55, etc etc. I've done all this during this recent test. So, I was no where near the combined of 17-20. Nada.

Update as of today (just meow). Helped a friend all day with his 84'. On the way out, he suggested to do the vacuum line trick with the Seafoam. So, we dumped half in the now on R gas tank, and the rest in the vac line closest to the fuse box. (couldn't figure out the one closest to the motor that sucked). So, that was the one that I chose. The funny part here, is it really had squat for sucking power. (like my exes). So, I wasn't even sure if it was the right line to use, or if it would even work, or wtf.

So, I shoved that line in there, and throttled it every two seconds. Holy crap. The smoke coming out of the back was nuts. I about had a heart attack. Pulled out the line and checked suction. Holy crap. I haz suck power! Finished the rest of the bottle off and reved it. Checked the suck power on the line again and felt it could suck a golfball through the line now (again, not like my exes).

Needless the say the drive home was boneriffic. It's like a new car. I put 5 gallons in the tank (regular) and marked the trip meter at 512. Got home and it's at about 530 (not going back outside to check). The mark didn't move from where the fill took place (just slightly past the 4th marking).

So, I'll be watching it.

I think this may be it. No vacuum=not a happy car! LOL!

944Ross

There is only one way to check gas mileage, period. Fill completely, drive a significant distance (not 5 or 18 miles), refill completely, note mileage travelled. Divide miles travelled by refill amount. Estimating off the gas gauge is a complete waste of time, particularly near the top of the range (Full). Calculating off less than a hundred miles is also inaccurate.