1996 Chevy Astro sluggish acceleration / power loss

BATTERYMAN

MEMBER
1996 CHEVROLET ASTRO
6 CYL
2WD
AUTOMATIC
208,000 MILES

Bought used from guy that said wasn't running. I pulled & reinstalled fuses and relays in fuse box and it started up but was idling and running rough. Tried fuel injector cleaner w/ little or no affect. On the road it runs decent on flat road but hard accelleration or going up hill makes motor choke, sputter and lose power. I then replaced all spark plugs, plug wires and rotor. It now starts and idles much smoother but same result as before on the road test. In idle you can rev motor fine but put into gear and under load it may start off fine but then does what I said on the road. The guy before me had the fuel pump replaced but that didn't fix the starting problem with him.

What should I try next?

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

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