Lurching/ bucking at low rpm's

[buckwheat]

I have had an issue recently with my 87 4.0L 5 speed MJ. At low rpm's my truck will buck/lurch and have almost no throttle response. Sometimes it will die even with me feathering the gas like crazy. It seems like its not getting enough air, or not enough gas. This problem is much worse when starting in 1st gear, and the absolute worst when trying to reverse. To make things better it is somewhat intermittent. 

 

I put a fuel pressure gauge on it, and while it would read 31 / 39 like it was supposed to, when I opened the throttle the pressure would drop to 23 for a few seconds before coming back up to spec. I thought the fuel pump was the problem, so I replaced that, and the fuel filter. The lurching and throttle response is much better now, but still there. So I am wondering what else could be going wrong?

 

My next thought is the TPS and IAC i put on it from Orielley's were cheap and are failing after 1 months use. Should I be looking for replacements for them? Or does anyone have another idea what might be going wrong?

 

I have done Cruiser's Tips for cleaning grounds and connectors, as well as eliminating my C101. The TPS is adjusted to spec using Cruiser's instructions as well.

[fiatslug87]

Make sure the EGR valve and transducer are working properly.

http://comancheclub.com/topic/28026-egr-valve-vacuum-issues/?fromsearch=1

[buckwheat]

I recently replaced the EGR with one from an 89 XJ. The one I put on had a transducer, while the one I took off did not. Was there a change in the EGR system from 87 to 89? 

 

Can I rent a vacuum gauge and hand pump from Orielleys (or similar)? Or are they cheap enough that I should buy my own?

[buckwheat]

Sorry to drag up something so old, but I just made progress on this issue. I capped off the vacuum line leading to the solenoid, and almost all of my issues went away. So I would like to get rid of my EGR. I have read many different web pages and there seems to be a 50/50 split on whether it is acceptable or not. So I guess I am wondering what the consensus of ComancheClub is. Can the EGR be deleted without any ill effect? I am hesitant to replace the EGR since it costs 150 and is another piece that can break at a later date.

[Jeep Driver]

Delete it!

[gogmorgo]

The only reason to hang onto the EGR is that it's mostly illegal to remove emissions equipment. Oh, and I guess the reduction in emissions. If you're suggesting deleting it, I suspect no one in your area cares much either way.

[Rockfrog]

Mine was removed 2 days after I got the truck. It was all NFG and needed replacing anyway. Still pulled 22mpg hi way. No overheating, a bus load of nuns/school kids didn't spontaneously explode. Trucks been running fine the last two years now, about 34,000kms so far.

As gogmorgo mentioned ... The issue is area legality, not so much function.

[buckwheat]

Awesome. As soon as I get the chance it will be gone. What did you all use to plug the hole in the exhaust pipe?

[Rockfrog]

Originally I left it inplace but disabled the valve (the valve is closed normally). Just removed all the EGR vacuum hosing, transducer and solenoid. Then finally removed it altogether when I swapped an HO head intake and exhaust a couple months ago.

The pipe is threaded the same as an O2 sensor M22 so an O2 sensor plug will work. You could always do the fold and crimp, fold again and crimp. Done that on a few vehicles.