Engine rattle while accelerating but stops while idle: Jeep Ch. 95

If it whines when moving and not moving with the engine running,it may be the fuel pump.

Could be catalytic con.in side.

The lost acceleration is of major concern. Maybe you have lost your water pump. It would work great for a few miles when you start out and then gradually heat up and loose performance. The fluid would eventually boil over? Maybe a bearing on the camshaft is expressing it's discontent and causing extra load for the engine to overcome. Try to determine where the noise is coming from.
The serpentine belt connects the alternator, water pump, power steering, front timing pulley, fan, and front timing pulley. All these components generate a parasitic load on your engine. If the engine has to work harder because of increased load it could be any of these components. I'd definitely check the water pump listening for noise while running. Look for obvious things related to the belt and its' components.
Check the serpentine belt for wear. May indicate pulley misalignment or wear. There exists two idler pulleys that have small bearings that wear out and squealing noises. Check those for wobble with the tension off the belt. They are pretty cheap so replace them if any concern at all.
Power steering pumps cavitate and make a high pitch gear whining sound if fluids are low or gears warn of. Check the fluid and top off to the correct level.
Best wishes,
TF

Check the belt tensioner and the idle pulley... (looks just like the pulley on the tensioner, but bolts straight in.).. - from experience...my single pulley was bad... after replacing the tensioner TWICE... (duhh!!)

Remove the serpentine belt notating the direction of travel. Start the vehicle long enough to confirm the chirp is either still present or it has stopped.

If the chirp stops manually spin all the pulley by hand to see if you can duplicate the sound. If nbothing else is making noise and the belt is in good shape put the belt back so that it travels in the opposite direction. If the noise persists replace the belt. If the noise goes away see how long it lasts. I have had many that have not returned after rotating the belt.

One other thing you can try is putting a small dab of di-electric grease on the belt, with the engine off of course. Spread the dab around a little with a finger, again with the engine off. Start the vehicle, give it a couple of seconds to let the grease work around the belt. If the noise goes away replace the belt.

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The noise you are hearing may be caused by a loose or worn serpentine belt and is slipping during all engine speeds while under load. It could also be a worn serpentine idler pulley that has worn out. These are just two areas for you to consider,but it is hard for me to tell without actually hearing the noise. Take the vehicle to an autoparts store and have someone check these engine components for a possible cause. They won't charge you anything.

check the tires for separations or bulges in the tread face also check the drive axles see if the boots are torn or missing all together,also be sure to check the ball joints and tie rod ends.

Check the idler and tensioner pullys for your serpentine belt. I suspect the whining noise heard earlier was due to the fact one was getting a bit stiff or rough turning. When you gave it that extra fuel, the sudden load may have finished it off. Sometimes they lock up, and sometimes they fall apart. Check those items first.

Loosen and remove the Alternator belt which may be a serpentine belt and see if the whining goes away.
It could be the alternator or the water pump if it's driven by the same belt. It will go away while moving because the engine noise is usually negated by road noise etc but it's probably still there.

Could be anything that is attached to the serpentine belt. ie: starter, water pump, A/C compressor, tensioners, steering pump.

My guess is a bad idler pulley bearing (cheapest to replace).

How many miles, what year is vehicle?