Just Baffled, stumble, die

[bugsjeep]

Hello, I am not sure if this is right place for this but here goes. I have a 1990 xj, always ran great. I have recently replaced IAC, TPS, MAP, MAT, O2, O2 relay. I have even put old parts back on to eliminate each part replaced. These new parts were put on over the last 6 months or so, not for any real reason other than I don't know what is original or not so I just wanted new.
I have very recently installed a RADesigns rail shifter and lock out switches.
My problem is this, as I drive after 5-10 minutes it will stumble, sometimes almost dying, in fact if I am stopped and it stumbles sometimes it does die. It seems to be getting worse, at first it would stumble a couple times and then be fine rest of day. Last time I drove it, I was moving about 50 and it was just like you shut it off, I pumped gas a few times, it took off again, I am not saying gassing it did anything, just a reaction to it dying for a second. It does have a new Bosch fuel pump as well.
If I disconnect the battery and then connect it nothing weird happens, but, if I disconnect neg side, ground it to pos side to drain capacitors to reset everything to "zero" then hook ground back up, I get an electrical buzzing from drivers side, near firewall I think, lasts for a few seconds then stops. don't know if it is related to dying either, just an observation.
Driving me nuts, I know diagnostics by print if an iffy science, but I any ideas are very welcome.

[4.3LXJ]

I am assuming no codes?

[bugsjeep]

I don't have a obd1 reader, I am thinking it may be a good investment. Thinking about the snap on 2500 but being a discontinued item, I need to make sure if I find one it has all I need to plug into and connect with the jeep.

[4.3LXJ]

I am thinking that you may have a crank position sensor starting to go. They can make the engine die intermittently among other sykmptoms. How long since it has been changed?

[bluedragon436]

I agree.. was going to originally say Throttle position sensor, since you were saying you could kind of reset the gas pedal and ti goes like nothing is up.. But if you've just replaced that and tried swapping the old one that worked fine back in and it still does it... would almost say take a look at the crank position sensor, as that is kind of the same thing mine was doing right before it went completely out on some rail road tracks...

[bugsjeep]

I am thinking that you may have a crank position sensor starting to go. They can make the engine die intermittently among other sykmptoms. How long since it has been changed?

never since in my family 6 or 7 years and it has 277,000 miles

[bugsjeep]

I agree.. was going to originally say Throttle position sensor, since you were saying you could kind of reset the gas pedal and ti goes like nothing is up.. But if you've just replaced that and tried swapping the old one that worked fine back in and it still does it... would almost say take a look at the crank position sensor, as that is kind of the same thing mine was doing right before it went completely out on some rail road tracks...

HA, ok well I have a new one ready to put in, I think I will do the cam sync too while I'm doing tune up, I have a new one of those as well.
Now if it were mine that died on the tracks, depending on how much grief it gave me that day, I might have just walked away...

[bugsjeep]

I want to say thank you to everyone on this site for reading my problems and trying to help. I am on a lot of different forums, boats, bikes, different cars, welders, machine tools, but I must say, I get the quickest responses on this (and other...to be fair) jeep sites.