1990 4runner MPG

andrewhove

New Member
Joined
Jan 24, 2008
Location
Durham
Ok here's the deal. I recently bought a 1990 4runner 4cyl Auto.

I bought it in Virginia and on the way back I got almost exactly 20 mpg (19.8 if I remember correctly)

After I got it back I changed the oil, air filter, did a tune up. Cap, rotor, plugs, wires etc.

I know have it at school in Chapel hill and drive it mostly around town and back home to Durham every once in a while. The past 3 tanks have posted HORRIBLE mpg number. like 10-11 mpg. I can't afford to drive the thing when half a tank literally gets me only 70 or 80 miles. it's just absurd. I drive like a grandma and got about 17 in town and 21 highway with my old runner which was 22re stick.

My question: Is there something wrong with the engine? or is its gap between city and highway really that big?

thanks
 
i wouldn't think there should be that big of a difference. i would check all the stuff you did and make sure that its all in spec. i got around 15 mpg in my 84 carb on 35s and stock gears. that was about 90-95% around town
 
my '90 Runner ( 5spd, 22RE ) never got better than 18mpg " corrected for tire size " on 31x10.5s

driving from Archer Lodge to Raleigh everyday was about 15 at best, but most was used sitting in traffic at the time.

I could see where an auto could suck up a lot more mileage.

How much idling does the truck do?

does it ever get hot ( normal operating temp) ? check that the T-stat is working properly, if stuck open, it'll never come out of open loop, and use more gas. ( ECM still trying to warm engine up to operating temp, it's like driving with the choke closed on a carb engine )
 
O2 senser maybe. my Cherokee all of a sudden got more horse power and less MPG's it was a bad O2 sensor...it was running rich...just a shot in the dark
 
Since the MPGs were good before the "tune up", I'd start by looking at the things you did there. Something is definitely amiss.
You changed the plugs - what kind/style did you get? How did the old ones look? Pull the new ones and look closely for evidence or abnormailities. What rotor/wires etc?
 
The plugs were NGK i think. The ones I took out looked terrible. Gaps were all wrong and pretty brown. Ones I put in look great.

Cap and wires were Napa, the nicer line of stuff they sell.
 
andrewhove said:
Cap and wires were Napa, the nicer line of stuff they sell.
Click to expand...

all the years I had 20R-22RE engines, the only wires I found worth a damn were OEM and a few sets of Accel make your own wires ( cut to length and crimp )

most problems I had out of after market wires were the boots at the distributor and coil didn't seal worth a damn causing misfires and erratic running.

As for the "higher line" stuff the parts stores sell, ask to see both products, a lot of times, the only difference is the price, and the high line stuff might have a reasonable warranty, and a pretty box.
 
^^ pretty much the same experience re: wires etc.
I always thought that was hocus pokus until I expereinced it in person.

How does the motor sound at idle? Did you adjust/change anything during the "tuning" or just replace stuff?
 
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