Mechanics

SLOW?

1991 Isuzu Stylus

Engine Performance problem
1991 Isuzu Stylus 4 cyl Front Wheel Drive Manual 113000 miles

i have a 91 isuzu stlus that I just traded my dirt bike for.
first off it gets only 20 miles to the gallon. I have replaced the spark plugs, wires, cap, rotor, air filter, and oil filter. It still gets terrible gas mileage. What should I do about that?

secondly it idles rough and I have taken it to a mechanic and he did a diagnostic and he said it passed with flying colors. It has a new muffler, water pump and radiator.
what about all that?

and lastly, when I am driving sometimes the acceleration dies, it just looses speed and then picks back up, and this happens randomly a have not been able to accociate a consistent pattern, could this be why the car is getting such bad gas mileage? Its inly a 1.6 I would assume that it should get around 30+ mpg.
thanks
Chris
Avatar
Chrisritter23
February 25, 2010.



Hesitation and lack of acceleration: Inspect and test all the following listed below: Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note: If it doesn't apply disregard.

Rasmataz
Feb 25, 2010.