Gas milage?

[Jerry Hunt 10]

I have a buyer interested in our car. One question that I could not answer because my son never kept track was a realistic miles per gallon estimate. Any help would be appreciated.

[NCReatta 210]

I have a buyer interested in our car. One question that I could not answer because my son never kept track was a realistic miles per gallon estimate. Any help would be appreciated.

On my '89, I get about 17 city, 22 highway. I don't have cruise on the highway, and I admit I'm a little bit of a lead foot

[Northwestsun 10]

Jerry,

I drive over 400 miles a week commuting to work. Bulk of this is freeway and I use cruise whenever I can around 60+ MPH. I am getting just under 25 MPG with all this. Car came to me with a K&N air filter, for what it's worth.

Dave @ Northwestsun

[Bushwack 41]

FWIW, stop and go traffic - 13-14 MPG. Highway driving (120 miles): 28 MPG at 65MPH with about 50 lbs in the trunk. YMMV.

[SeanR 3]

Mine is mostly stuck between 17.1 and 17.5. Sometimes 18. I drive up a road to/from work mostly called Tiger Mountain...so the MPG's gets sucked going up and sometimes go back up just a tad when coasting down.

[DAVES89 866]

On both my cars I get 28 on the highway w/cruise set at 70MPH around town 19 to 21. Average about 23-24 MPG.

Edited April 24, 2012 by DAVES89
Average 23-24 MPG (see edit history)

[reatta1991 10]

On my 91 around town, about 18. On the road, mostly 55 - 60 mph, around 21-24. Hills keep it around 21, on the flat on the higher end of the range.

[mongeonman 2]

highway=29mpg on my 88 and 90 convertable at about 65 mph

[Richard D 10]

90 Coupe with 145,000 miles. A/C on, 14 stop-n-go, 29 at 70mph cruise control on

[Jerry Hunt 10]

Thank you everybody that responded. I figure that if I say 18city and 24hiway it should be pretty accurate.

[NCReatta 210]

Thank you everybody that responded. I figure that if I say 18city and 24hiway it should be pretty accurate.

I would say so.. Perhaps a bit high. Just depends on the car too.

FWIW, I drove the convertible 200+ miles today. Averaged 22 mpg. Average speed was around 55 mph.

[Claret Red 89 10]

I was thinking of asking this same question. It appears that the mileage estimates are all over the place. The realization that people have different driving habits accounts for alot of the differences, but that shouldn't make a difference of up to 7 mpg for highway driving.

I recently had a new ECM installed in my car and my stop and go mileage went from 17-18 to 14-15. I haven't had a chance to check the highway mpg, but I expect it has also dropped.

Is a there a "computer relearn", or some other factor(s) associated with a new ECM that affects gas mileage?

[KDirk 330]

A new ECM usually required a "re-learn" period before the long term fuel trim and so forth are calculated and stored. I think I was once told by a mechanic (whom I trust) that about a weeks worth of normal driving is enough for this to take place.

FWIW, I must have lead soles on my shoes because my average combined (directly from the CRT) in my 88 is 14.8-14.9 consistently. Granted, I have more stop and go than highway miles, but some of you guys are making me jealous with your 18+mpg figures. When looking at the real time instant readout on the CRT, on the highway I can easily maintain 23-25 mpg even with light acceleration to maintain speed on flat road, so I don't suspect anything wrong with the car mechanically.

KDirk

[Claret Red 89 10]

I don't like looking at the real time fuel mileage on the CRT! The car is just too underpowered I think. It takes forever to get up to speed without a little lead foot. I have been told I am a "lead foot", but when I try my best to get the best in town mileage it is normally within 1 mpg of my normal driving habit mileage.

[Bushwack 41]

I don't like looking at the real time fuel mileage on the CRT! The car is just too underpowered I think. It takes forever to get up to speed without a little lead foot. I have been told I am a "lead foot", but when I try my best to get the best in town mileage it is normally within 1 mpg of my normal driving habit mileage.

Just a thought. I recently changed the catalytic converter (and muffler) and noticed a significant increase in power. MPG difference is negligible but can't be definitive because I didn't monitor usage prior to the new cat. But again, I was surprised at the performance bump with the new cat.

[NCReatta 210]

Just a thought. I recently changed the catalytic converter (and muffler) and noticed a significant increase in power. MPG difference is negligible but can't be definitive because I didn't monitor usage prior to the new cat. But again, I was surprised at the performance bump with the new cat.

I agree. If you have had a misfire in the past, that can clog the cat up really fast.

[89 Maui 13]

Kevin -

The Reatta was promoted as a personal luxury car not a sports car, keep your foot out of the injectors and enjoy the car.

When I bought my '89 last May I drove 750 miles straight interstate and got 28.8 mpg but my latest in town is 17-18 mpg and I installed a new ECM last August.

And I still have a E026 code that I haven't found yet.

[KDirk 330]

Woody,

Yeah, I don't really lay into it very hard except if doing an "evasive pass" on the highway, and I certainly don't drive it like it is a sports car; which it isn't. I do tend to be a little quick off a stop light and generous on acceleration, a habit I have been trying to break. I am not quite as bad about it now as I use to be, but clearly have room for improvement.

Starting to think I may need to look at a cat and muffler, as the 88 had many problems in the past (prior to my ownership, all sorted out now) with poor running due to a bad ECM, MEM-CAL and mis-routed plug wires. I suspect some damage was done to the cat during that period of time. I can't say it feels starved for power. In fact it seems to have more zip than my 91 with no cat (removed prior to my ownership of the car) so I've not been too concerned about it to this point.

KDirk

[DAVES89 866]

I just got back from driving mostly highway on a fresh tank of gas. 300 miles, average speed 59.8 MPH and 27.9 MPG. [According to CRT]

Also looked at CRT [memory] and last tank was average 30.8 MPH and 20.9 MPG [334 miles]

[wws944 100]

"To measure is to know." If you are wondering if the cat is causing a backpressure problem, it is easy to measure it. Just remove the O2 sensor and use a pressure gauge. Random googling turned up: Exhaust Backpressure

[wally888 0]

On both my cars I get 28 on the highway w/cruise set at 70MPH around town 19 to 21. Average about 23-24 MPG.

Had about the same figures on several coupes-a little better on 90 ragtop-a little less on a 91.

Gear ratio is not the same for all years!

[NCReatta 210]

I got 27.5 today. Top up, ac on. Cruise set at 70.

[padgett 2,426]

Tire pressure can make a suprising difference 26 psi=24 mpg on I-4, 32 psi=27 mpg same-same.

3800 (and any engine with a really flat torque curve) is deceptive about accelleration, it is just suddenly going faster than you intended. Some years ago I tested my 88 and 0-60 was mid-8 seconds.

Keep in mind that the 3800 is a mid-80s redesign cam-in-block iron engine originally from the early 60s. There is quite a difference that the last two decades has made. My new tow car (son has TranSport) is a 4400 lb behemoth with a 3.6 V-6 that gets better mpg than my Reattae. Of course it is an alloy 6400 rpm 290hp FI DOHC with VVT i&e & 90% of its peak torque from 1600 to 6200 rpm. Does run hotter than I like but will fix that.

Like the Reatta though, the vitually flat torque curve has no feel of accelleration, it is just suddenly going very fast (and 0-60 is a full second faster than the Reatta). Nice thing is that if things really go bust I can just build a still in the back yard and run on that.

Like a Rolls-Hardley, I just think of the 3800 as "enough".

[Buick City 30]

I have a "89" & "90" -both average 27 on hwy. I bought another "89",and the best it would do was 17.I looked at the # on the injectors,and it had a higher # than on my other 2 reattas.I replaced the injectors with the same # as the other 2 and now it gets 21. ( am still trying to make it better) On a straight drive (without stopping) the best I ever got was 32mpg for about 200 miles !

[padgett 2,426]

"32mpg for about 200 miles " - at 55 ?

[squiretom 0]

91 reatta local driving , half highway 55 , half in town with the ac on , 32 psi tires 18 to 20 mpg .have never had it running 70 for any length of time. 10 % ethanol is a real drag on economy at least 2 or 3 mpg loss.

i think 25 plus mpg needs a new battery in the calculator.

[padgett 2,426]

Haven't seen 30+ with a C 3800 since the 55 went away. Have seen 26-27 on trash gas. To get more today requires DOHC, VVT, and 10+:1 compression (and know of several that run on 87 PON).

[Buick City 30]

At 55-65 I went from Kingman Az.to Wickenburg AZ.& to Tonopah Az. didn't stop!

[wmptom 0]

Don't have my Reatta any longer, but I remember another forum which had window stickers that you could print, which had the mileage ratings. I had one, but it went with the car. I know that they were free.