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Q: hard starting then backfires when driving on 1991 Jeep Wrangler

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
155000 miles, ran fine until it started too backfire when driving and now hard starting. changed fuel filter, and new spark plugs,wires,rotor and cap.
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
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Sounds like timing chain worn out and possibly jumped a tooth. and/or possible valve problem. Do you know how to check either of these? Do you have a vacuum guage? Have you inspected plugs yet to see if it's only one cyl. being affected or all? I know you said you replaced them , but that will give you some useful info. Reply to this if you want more tips. Good luck. I also noticed a tip below my response that mentions common problem with TPS. Best get proper diagnosis first before wasting money on parts.
am starting with vac lines replacement since their look to be org ones. then looking at dist. since it is org. then going to timing chain. do you think it could be fuel pump?
Thanks for the feedback
If you can test the throttle position sensor that might save a lot of time and money. A dead spot(s) in that can cause those symptoms. Did you see the mention of 'repairpals. feedback regarding that and those jeeps?
Going that way now also pull gas tank found split gas line from pump to outlet connection line. filter was no good also. Look like I need to start one end and work to other end.
Thank again
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