I have an 1993 4 dr 5 spd.  It idles fine, but when I put it in gear and step on the gas I am not able to accelerate.  I am thinking it might be the O2 sensor.  Does anyone have another idea?  Thanks,

Is the check engine light on or anything else?

When was the last tune-up performed?

ditto tune up and CEL (MIL) lamp.
then check fuel pressure ( after fuel filter change)

or bad mAF , if the above not pan out, test it.


vacuum leaks gross.

remove o2 plug and eCU defaults to .5vdc.  (perfect mix) ECU lies to self , by design.
now see if this helps.

I presume car is lean, if rich and flooding ,well only you can smell that.

look at spark plugs, white/tan, or black and wet.?

if engine shakes, bad injector.  (dead or leaking)

Check your catalytic converters they might be plugged

Thanks for the suggestions.  No engine light, just the occasional brake light.  Tune up was said to be done a couple of thousand miles ago, but it wasn't mine then.  I guess I'll start there.

I have now replace the fuel filter, plugs, wires and disconnected the O2 sensor.  It  seems the idle is now getting worse.  I am starting to think injectors. Yes/No?


This engine seems to be getting worse.  It is shaking really bad and unable to drive at all.

Did you put the plug wires on incorrectly?

The 16V engine spins the dizzy the other way from the 8V engine.
check the firing order, re-connect the O2, even a bad one won't hurt
the performance, just sucks lots of gas, and check the cat for plugging,
also the timing should be checked, injectors and such don't go bad
often, so it's likely not that

Wild

Plug wire were swapped out purposely slow to mimic the previous wiring.  1|removethispart|@ TDC, 2 Closest to block, 3 |removethispart|@ Bottom, 4 near firewall.   I have tested and have good spark at all points.   I am at a total loss.

My dad had the same symptoms and it was the rear cat. it broke up and clogged the flow of exhuast. He could idle and drive slowly but no revs or anything over 20mph. Unbolted the exhaust and dumped out the ruble since we were there we went ahead and ppushed out the rest and reinstalled. Works great now, because the o2 sensor is before the rear cat.

Ran the truck long enough to get a code 44.  I will try adjusting the TPS today, if it doesn't snow too much.  I need to get a new exhaust manifold,  the number 4 has cracked almost all the way around.