Mechanics

CHEVY HESITATION AND LUNGING

1995 Chevrolet Chevette

Engine Performance problem
1995 Chevy Chevette V8 Two Wheel Drive Manual 195, 00 miles

My 95 chevy cheyenne 5.0 manual 5 speed lunges and hesitates when I accelerate. Idles good and start somewhat good. Afew tries usaually gets it. It has been sitting for awhile due to a tour in iraq, I was thinking it might be bad gas. Any help will do. Thanks
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Greengo
December 3, 2009.




Welcome back greengo and TY for protecting our freedom I did that 39yrs ago for my country too.

Okay lets start check the following below step by step and report back your testing results

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
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Tiny
Rasmataz
Dec 4, 2009.
Ok, well, I have replaced the o2 sensor, ignition control module and throttle position sensor. Ran some lucas injector cleaner through it. Checked the spark and its strong. Getting fuel to the tb, just cant check the pressure as I dont have a tester and dont trust it enough to drive it somewhere to have it tested. I put good gas in it out of one of our 5 gallon jugs. I'm really stumped. It's been tuned up. New plugs, wires, fuel and air filters. New distributer cap and rotor. Cut catalytic converter off thinking it might be plugged up. Still hesitating and bucking when I accelerate on test drives up the road. Slows waaay down on hills, Hoping that its not the timing. No vacuum leaks, checked that with some carb cleaner with the breather on. EGR seems to be in good shape. Took it off and it moves fine and returns to normal itsself. Dosent have a MAF sensor. I guess next will be MAP sensor, coil and fuel pressure regulator. But im gonna check the timing first before I sink more money into it. Probably wouldnt hurt to change it all anyways. Then if that dont work, fuel pump is next. Any suggestions would really be appreciated, tired of finding rides and walking.

Tiny
Greengo
Dec 7, 2009.
Well, my problem is fixed. It was my fuel pump. I changed it out my self, figured I would save a few dollars. It took a day to do it, but I made sure everything was done right. Got rid of all the old gas, cleaned the tank the best I could. Installed the pump and now she purrs like a kitten. Its a big weight off my shoulders. Thanks fellers, yall really saved the day. I will be sure to be back if I have anymore problems. Again, thanks so much. Semper Fi !

Tiny
Greengo
Dec 10, 2009.

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