I am wondering what kind of mpg you guys see on your wagons out on the road. mine is an 87 w/ only 109k and new plugs,wires,cap,rotor,coil... it is very smooth oout on the highway. Quick and good downshifts etc. most of the time I am out of the boost...

but I just took a highway trip Friday- Richmond to Washington- in medium to heavy traffic...Meant that my cruise was mostly about 75 mph but required some burst speeds up to 85+ occasionaly to get around highway left lane bandits creating big clogs.

Anyway I got 17mpg going up and 19mpg coming back . This seems low to me, most of the time I was not into the boost at all...so I wondering if this also may indicate the O2 is rich sense everything else in the ignition system is new.
Bosch suggests a new O2 can give a 10-15% improvement in mileage.

Also was not carrying more than 100lb load going up...just me coming back and closer to 80mph most of the time on the return trip.

Thanks

17-19 mpg highway is definitely not too good, even if you have the auto tranny. Usually I get 22-24 mpg for all-highway driving on my '93 945T (auto). I occassionally get the heavy-foot thing, and run mildly elevated boost (g-valve @ 9 psi).

Al gave you a pretty good list of suspects; one more possible run-rich culprit is your fuel pressure regulator (FPR).

The FAQ has lots of info on running rich, O2 sensors, etc. Check the easy stuff (tire pressure, air filter) first, and go from there.

- Brian '93 945T

Thanks for the link...please check out my reply to Al nd see if it suggests any other ideas.

David

Normal range is 26 to 27 highway, 17 to 19 city. Those highway numbers were at 65 mph with cruise and AC. At 70 to 75 mph you should get around 23 to 24 mpg.
Could be several factors affecting your mileage, yes O2 sensor going bad can cause a drop in mileage. Also check tire pressure and make sure air and fuel filters are clean and not clogged. Look for a vacumm leak it also cause a increase in fuel useage. Also using less than 91 octane will also decrease you fuel mileage. When was the last time you tuned it up and check the AMM's settings as well as the timing? Is the transmision slipping at the higher speeds? You should be running 3000 rpms at 80 mph. Sorry about all the info but usually it's not just one factor but many when our cars get up there in miles.

thanks for the feedback to everyone and the FAQ referal from Brian S.

Al, I got the car recently and I have done the following so far, cleaned out the "flame trap" crud (turbo Y and lines), new plugs, wires, cap and rotor, air filter, oil change/filter and complete auto trans flush using IPD kit, no slipage in trans are revs good at speed...replaced a couple of suspect vaccum lines and tried to look for leaks with a propane torch tube rig. I only use premium fuel.

I understand that timing is not adjustable but am going to run a light on it anyway...maybe the timing belt wasn't done right? I have not checked the AMM or the FPR yet... the car really runs great out on the highway...no odd syptoms at highway speeds,however, around town I am having an odd hesitation.

Not when cold, only after the car is warm and I stop for short while (like going to auto parts store) after a easy restart and smmoth idle the car will bog when I try to pull from a stop sign or light...only with the AC on.

Turn of AC and it gathers itself up quickly and runs normal in all gears...I will have to turn off AC at lights or stops (only) for about 3 minutes after that it runs great regardless.

AC system in good shape (serviced recently). The car runs great except for the poor mileage and the "weirdness" after a hot restart (and then only for a few minutes).

I guess that I will check timing, and the AMM connection (noticed in FAQ) and perhaps just repalce the FPR to be safe...car has 109k after all.

Any ideas and feedback arey very welcome and thanks.

David

What transmission do you have?

I have an M46, manual. I think it helps a lot.

I get about 27 around town. 33 on the highway if I'm careful.

But the difference can't all be about the trans!

It is an automatic...just did a complete flush and no signs of slipage. I agree it seems too low...please check out my response to Al and see if any other ideas come to you.

Thanks

17-19MPG on a tank for pretty much entirely highway driving does seem low. what kind of fuel (octane) are you putting in it?
--
Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

Only premium fuel...I listed the work I have done so far and another oddity in my replay to Al, please take a look and see if it sparks any ideas.

Thanks

I am getting about 22+.
I only run 92 or higher. I am running 12psi boost and do step on it alot. and still get about 22mpg. I know on highway I get about 25-26.
~Rich

Thanks for info. It does seem too low, running premium only too. In my reply to Al I gave him some other info maybe it will spark an idea.

Thanks