SideKIck 15 MPG ???????

[hiper]

PLEASE HELP
Hi Guys,
I own a 1994 Kick with 8v, went over unit a lot and tuned up but it is getting absolutely horrible fuel mileage and I am baffled why it gets this bad mpg
Any Suggestions would be hugely appreciated!!!!
Here is a list of work performed already!!

Compression is good
New Timing belt
WaterPump thermostat and all hoses
Plugs, rotor ,wires and cap
Wheeel bearings
Thorly header with new o2 sensor
Straight pipe back to magnaflow muffler
235/ 75 -15 Grabber AT2
Cold air intake

[fixkick]

welcome !!!
5sp or auto?
the pre 1996 cars all do that, easy. (when lame)
they can use 2 times the fuel wasted of the OBD2 cars, in limphome or if the ecu is lost control of fueling, (for example 02 stuck lean or exhaust leaks near it)
compression over 150psi? sure.
ECT read 300 ohms unplugged, key off? engine at 180f hot? full normal temps.
fuel pressure near 30 not 60psi.
no spark plugs soaking wet in fuel , say one plug its, suggesting an injector leak there.
does it misfire, ?
is the engine shaking at idle
does it idle at 800 rpm hot? holds,there, if turn on head lights and blower fan, same time does it hold 800 hot? (or if A./T box, shift to Drive hold 800 hot?)
key on, does CEL lamp glow key on?
then go out running?
did you use the diagnostic jumper yet, see code 12 flash out??
that is a start, no pun)

[hiper]

welcome !!!
5sp or auto?
the pre 1996 cars all do that, easy. (when lame)
they can use 2 times the fuel wasted of the OBD2 cars, in limphome or if the ecu is lost control of fueling, (for example 02 stuck lean or exhaust leaks near it)
compression over 150psi? sure.
ECT read 300 ohms unplugged, key off? engine at 180f hot? full normal temps.
fuel pressure near 30 not 60psi.
no spark plugs soaking wet in fuel , say one plug its, suggesting an injector leak there.
does it misfire, ?
is the engine shaking at idle
does it idle at 800 rpm hot? holds,there, if turn on head lights and blower fan, same time does it hold 800 hot? (or if A./T box, shift to Drive hold 800 hot?)
key on, does CEL lamp glow key on?
then go out running?
did you use the diagnostic jumper yet, see code 12 flash out??
that is a start, no pun)

Thank you so much for the quick reply.
I will go over your list . It is an automatic.

[fixkick]

ok automatics
hot engine, is 800 rpm
you shift to drive
rpm holds a 800. the ISC and ecu idle regulation servos do that. magic.

http://www.fixkick.com/CEL/CEL.html#OBD1codes

got 12 codes. its ok to even drive like that, flashing 12s,
usually it only changes for sensors fell off. its crude but worth looking.

15mpg?
not flashing 12s
02 bad, or ehxaust leaks to it, even new stuff, here can leak if not setup right. (cracks or on new system bad gasket near by)
fuel pressure not spec, running. 34-41psi , (changes by altitude.) lower psi at higher elevations.
injector leaks fuel (watch it at instant key off running, it must halt inject in same instant)
ECT reads wrong, or its wires fell off
02 heater dead.
wrong 02.
its not vacuum leaks, nor idle wrong. (although idle wrong is a clue to other things wrong)
is it misfiring?
are the spark tips black or fuel soaked.
maf dead, and ecu in failsafe due this .
there are other fail safe failures. using the jumper clip finds most.