Erratic Misfire

[CrunchnMunch]

I'm no expert,but mine does kinda the same,right after idle,as soon as I hit the gas it cuts out,then is fine after I get the RPMS up. EGR Valve perhaps? Mine is missing the hose on it I believe,or I'm guessing a vaccum line goes there? Sorry for the hi jack,just throwing out some info.

 

[89xj]

I'm no expert,but mine does kinda the same,right after idle,as soon as I hit the gas it cuts out,then is fine after I get the RPMS up. EGR Valve perhaps? Mine is missing the hose on it I believe,or I'm guessing a vaccum line goes there? Sorry for the hi jack,just throwing out some info.

i assume you have an 87-90xj if you have an egr valve. yes, the egr could be the problem if the vacuum line is missing.

 

[MUDDPUPPY78]

im no expert but through my own experience the cat could have a heat shield rattle and definitly check cps and wiring to cps. mine had exact same backfire/missfire for a few months till i figured that one out, no thanx to dealer and precicion tune but i still had to pay em 100 bux each before i left (for nothing)

 

[tugalo]

Mine missed at 1800-2000 RPM, hot or cold, and only in that RPM range.
Turned out to be a high resistance Manifold Air Temp sensor and intermittent grounds. another vote for additional HEAVY ground wires from block to firewall and battery negative post to front clip.