1994 engine surging What the #+@- is going on here?

[Ynot2691]

So I go to the store tonight in my 1994 explorer sport. Starts right up like it always does and runs like a top like it always does. When I go to leave it fires up and when I give it gas it jerks really hard and when I give it gas the tach is going crazy as the engine is kind of like surging with no power to move the vehicle hardly. I pulled over and looked under the hood for any obvious problems which of course there were none. I checked all the connections I could get at. All good. Started it back up same thing. Plugged in my code reader to see if there were any codes. Only for the stuff I unplugged. Fired it up again, ran fine. Anybody seen this before. Im at a loss at this point.

 

[yostyexplorer94]

If I am understanding correctly, it started to run fine again.
So it would be an intermittent problem
I had a bad wire connection on a new fuel pump that gave me similar issues like that.
I would start with checking the fuel pressure at the engine. Check for vacuum leaks.
Could be a bad fuel pump relay. Can try replacing that when it acts up to see if that changes anything

 

[ChildIdenticant]

hate intermittent problems ... As your sport had some kind of obdII prototype hardware I wouldn't assume anything about your vehicle. And I wouldn'teven assume any modern dealership tech would know how to properly uninstall such a thing with guarantee to return vehicle to stock condition. I still think you got the short end with just 2500 and motor mounts. Surprised an offer to buy the entire vehicle wasn't made.


condition explanation, is :
vancuover Washington at evening<33ºf
(cold?)normal start - drive of undisclosed time/distance
park of undisclosed time
(cold?)erratic start with erratic tach display

So you have a manual, can rule out weird automatic vb things.
You recently replaced master cylinder.
You recently replaced the clutch.
You did a bunch of work in september and you mention coolant leak and extensive effort on the exhaust removal. The work done in september may have disturbed something (don't know how often it's driven).

If the rpm climbs erraticly, in gear, with no/little power, I would first investigate the clutch&mc work recently done.