Losing Power under Acceleration

When I'm driving my Jeep, right after starting it within about five minutes of putting it in gear, I can press on the gas pedal and it does not accelerate and if I press harder on the gas pedal, it makes a knocking sound and I can feel it through the pedal as if it is coming from under my feet. It doesn't stall out but does act like it is starved for fuel. When I let up on the gas pedal and then press back down, it seems to correct the issue most of the time.

What I am thinking is that the IAC needs to be cleaned and perhaps new spark plugs? I'm just sort of guessing at this point, is there someone who has an idea what might be going on?

The knocking could be pre-detonation, which is a quick way to destroy a motor.

I tend to get pretty methodical when troubleshooting. First I would pull the plugs and get a reading. Post up the pixs and we can help you with this. Keep track of which cylinder each plug came from.

While the plugs are out, do a compression test, both wet and dry.

These three tests will tell you a lot about your motor.

By the way, not having the year model limits the help we can give you. Also, what is the transmission? auto/manual

It's a 1998 with an auto transmission. The engine isn't knocking, it just stops accelerating momentarily and then once I let up off the gas and press back down, it accelerates just fine.

vikingxj said:

When I'm driving my Jeep, right after starting it within about five minutes of putting it in gear, I can press on the gas pedal and it does not accelerate and if I press harder on the gas pedal, it makes a knocking sound and I can feel it through the pedal as if it is coming from under my feet. It doesn't stall out but does act like it is starved for fuel. When I let up on the gas pedal and then press back down, it seems to correct the issue most of the time.

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This may be what's confusing the issue

When my torque converter went south, it didn't knock but it did make a whirring sound that I felt through the pedal and sounded like it was directly under my feet. when it died, the truck wouldn't GO...it ran fine engine wise.

To me, it seems like it is just not getting enough fuel/air mix when I'm trying to accelerate. It isn't a "knocking", like inside an engine, but rather when I press the gas pedal as it is losing power, it makes an audible noise.

As suggested already, inspect the spark plug condition and color.

Perform a full tune-up, including a new coil. Once you have a solid base-line, if the symptom's persist, suspect one or more OBD engine sensors. Test the TPS, Test the O2 sensors, and test the Coolant Temperature Sensor.

It seems as if you are describing when the PCM changes from open loop warm-up operation to closed loop operation and it is seeing OBD sensor issues. Bucking, stalling, and/or backfiring should make one suspect a weak or faulty O2 sensor.

It is rather unlikely that the torque converter is the source of the symptoms.