I have a 94 jeep cherokee se. I love it and it has 269,000 miles and it's been a good one.

On to the problem. Here are the symptoms.
- It jumps when it idles but not really bad and sometimes it doesn't do it at all.
- it jumps pretty dang bad when driving down the road especially around 45 mph or when going up hills.
- sometimes it doesn't do it nearly as much or bad.
- if I let off gas when it starts doing it. It stops.
- it's bee doing this for a long time. I changed the plugs and wires back when it first started and it didn't stop.

If it is the egr valve how do I take it off to clean it or replace it? Any good links with pictures on how to do this?

 

Don't know if this helps. My experience with EGR Valves are. 1. You'll get a check engine light.
2. Valves will start tapping upon accelerating and when cruising.
3. Engine will diesel when you turn it off.
If your EGR Valve is the diaphragm type, you can squeeze the diaphragm with the engine running. If the idle changes. Goes down. Its good if not. Likely bad.
They can sometimes get plugged with a small chunk of carbon. I took one off a CJ once. Lightly tapped it on something. Some small black pieces of carbon fell out, similar to what is used as filter material in home aquariums. From the on, it worked.

 

When you say knocking could you mean like a ticking sound when starting off be cause mine does that sometimes. Not always though.

Where is the egr valve located? Sorry if I sound stupid but I really need a step by step because I'm trying to learn more about how cars work and the egr thing is new to me.

 

Just realized why I felt stupid for not being able to find the egr valve. My year model doesn't have one.

So now I'm wondering what is causing the problem. Could it be the catalytic converter? I'm stumped.

 

Have you cleaned the throttle body and IAC?

 

No I haven't. I looked it up and it seemed pretty easy but could that be the problem? It does it worst while driving. It doesn't really do it while idling just occasionally and when it does its not that bad.

It always does it while driving: from not as much to really bad. If I let off the gas it stops though.
It seems like it would be a way to fix this.

 

Easy to do and can't hurt. Tested fuel pressure? Fuel pump may be going south....

 

Yeah it couldn't hurt to do that. I'm also wondering if it could be a vacuum leak somewhere. It's weird that it seems to do it worse, when it does it, around 45 mph.

 

Ever replace the plugs wires cap and rotor?

 

No I've replaced the spark plugs and wires back when it started but it didn't help. I'll give it try though.

Someone told me and I looked it up that it might be clogged or dirty fuel injectors.

 

I would also check the TPS. If there is a dead spot inside the TPS that could explain your problems. the test only takes a few minutes.