I have replaced air filter, dist. cap, rotor,wires &plugs, O2 sensor, crankshaft sensor, IAT, & CPS. TPS is good have checked all vacuum lines. Replaced all "O" rings on injectors. Fuel filter, checked the PSI & reads a steady 30-31, Checked catalyst for clogs & found it to be gutted. Has EGR "eliminated" as per Memo. Renix 88 AMC 40.l has NO reading {'87 - '90} cannot stop it from backfiring @ 12mph/15/25/35 ... it will only run smooth if I "baby it" & keep the acceleration to a minimum. The more I put in to it, the worse it runs. I love my Jeep, but hate what it's doing. H E L P !!!!

Get a tune up . wires plugs cap rotor , Clean MAF , replace TPS . etc.

I'LL TRY, GOOD TO SEE SOMEONE TRY AT LEAST ! IDLE SEEMS HIGH, BACK TO BASICS !!!!!! THE AIR & FUEL FILTERS NEED REPLACED, SPARK PLUG WIRES, YOU FORGOT THEM !!! DISTRIBUTOR CAP & ROTOR, YOU FORGOT THEM !!! THESE ARE AS IMPORTANT AS THE AIR WE BREATHE !!!!! VACUUM LEAKS, CHECK ALL VACUMM LINES, THOROUGHLY ! THIS LINE COMING OUT OF THE TRANSAXLE PORTION OF THE INTAKE MANIFOLD ?????????????????/ YOUR NEED TO REPLACE WHATEVER IT IS, WHAT KIND OF LINE ? METAL, RUBBER , WIRE ??? MOVING ON, GOOD YOU REPLACED THE OXYGEN SENSOR, & IDLE AIR VALVE, & TPS, RECHECK TPS, IS IT LOOSE, ALSO TIGHTEN THROTTLEBODY BOLTS, THE ONES THAT HOLD IT DOWN. SO, CHANGE YOUR FILTERS,WIRES, ETC., MENTIONED ABOVE, CAP & ROTOR, ETC.,ETC.,.........GO FROM THERE, SEE HOW THAT WORKS

Have u checked the cadeletic converter. It can do funny things

Check for vacuum leaks. See tips at first link below.
There is a test for the tps at the second link.
Do It Yourself


Repair Guides Fuel Injected Electronic Engine Controls Throttle Position...

got me thinking, have you bore scope your cylinders to check for carbon build up,this will cause pre-ignition depending on how bad it is, also have you check your fuel press and volume it maybe running way to lean, hope it helps you .
good luck

try to spray some carburetor cleaner inside where the air goes in the engine...it will clean the system and it might start...
press some gas when you try to start the vehicle...
good luck!

Check all the sensors

bad sensor

next time i repair a jeep i will have a look at the one on the front .personally i would try changing the cps first its the easier to do and the most common fault

could it be your throttle sensor? If it is a carbureted engine, check the accelerator pump inside the carb.