89 sidekick 1.6L 2dr 4x4 A/T

[fixkick]

Hi all, 
thanks to everyone who's contributed to this site. It's been super helpful. 

89 sidekick 1.6L 2dr 4x4 A/T

CEL on with Key, off when started. Code 12 when codes pulled.

Vehicle warms up to 180+
Cold start 2000 rpm
Idle drops 500 within 30 sec to 1500 rpm
When warm 800 +- 50 rpm  (normal that is)
Load on 950 rpm (normal see fast idle up  , diode block under dash)
Compression 170-175 psi across all cylinders. very good.

New parts

TB all gaskets.
Air filter
Timing belt
Water pump 
Plugs
Wires
Coil
Distributor and rotor 
O2 sensor
ECT 
Oil pressure sensor
Complete exhaust (except manifold)
Vacuum modulator 

First let me say that my rpm isnt completely stable. It fluctuates up and down +- 50 rpm at all times. that is normal and spec.

Using the propane technique I've discovered if I apply propane to back side of EGR (where you push for stall test) the idle increases.
I assume this is suppose to be air tight? No other areas see any rpm change with propane applied. You assumed correct that EGR is sucking air , vacuum leaks,

Second issue is, when I put into gear the rpm drops 200-400 rpm and will not recover.  (that is wrong) ISC is dead, why can be complex)
With any electrical load (headlights, heater) the rpm increases about 150 rpm.

I was willing to live with these issues until a few road trips have shown I'm getting 18 mpg highway. 26mgh normal, not 18 unless driving 85mph all the time..
Other things to consider is I'm running a 2 inch lift with 31's. (that makes the odometer lie big time it runs slower, the taller the tires and lies on distance and MPG is based on that.

With stock gearing. From what others have posted this seems to be horrible mpg.  i have the correction page here.
named gears. use a hand GPS for distance, and see the here , i think 10% but dont know your rim sizes (circumference is the key fact)

https://fixkick.com/part-time-test.html#SPEED

lots of reasons for mpg low.

https://fixkick.com/MPG.html


Anyone have any input? Thanks

good luck you  and your 89.  if the VIN starts with letter J, they made the first ones in actual japan then later 2cn canada prefixed VIN