transporter Posted May 25, 2016 Share Posted May 25, 2016 Hey Folks, The wife just bought a 93 Wrangler 99k on the odometer. (Slight problem after shifting to 2nd or 3rd gear and give it gas (doesn't matter how much) - the Jeep surges (or bucks). An exceptionally clean machine. Previous owner just installed a New clutch, water pump, radiator, battery, rear springs, CA smogged... 35's, 4.56 gears, spring over 4" super lift (yes a stiff ride),front True Trac with cable engagement, rear Lock rite locker, 5 speed. I went over the Jeep with a fine tooth comb - made new bracket for front track bar and installed it, installed new rear mount for rear track bar bracket, new rear shocks, made my own transfer case torque rod bracket, recabled winch, ignition cut off switch, remounted spare tire to rear bumper... and on and on. So, I thought I would start here before I started trouble shooting the bucking or surging issue, to see if anyone had any ideas. The previous owner said it started when the rear lock rite was installed. I have owned a lot of Jeeps and cannot figure this one out. Thanks for any input. Pete Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted May 28, 2016 Administrators Share Posted May 28, 2016 Any codes thrown, Pete? Surge is often O2 sensor or TPS switch related. Each is a possibility with a 4.0L at 99K miles...If bad enough, there's a code. Is the exhaust okay and unrestricted? Pull at least one spark plug and see what's going on with the combustion...Check for vacuum leaks, there are plenty of vacuum bleed-off points on a YJ Wrangler, including front axle disconnect, though your YJ has a cable actuated disconnect, right?...We can go from there. Quote Link to comment Share on other sites More sharing options...
transporter Posted May 28, 2016 Author Share Posted May 28, 2016 Hi moses I appreciate your post response as always. a brand new California exhaust system was installed prior to purchasing this Jeep brand new header downpipe catalytic converter and some sort of performance muffler that actually sounds pretty good for the six-cylinder. No codes have been set, I will definitely check out your excellent suggestions, standby I will do some troubleshooting and get back to you thanks Pete Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted May 30, 2016 Administrators Share Posted May 30, 2016 Great photos, Pete! Nice rig and equipment...Looking forward to your findings. Moses Quote Link to comment Share on other sites More sharing options...
transporter Posted May 30, 2016 Author Share Posted May 30, 2016 Moses, in the interum and after watching all the YouTube videos and researching the throttle position sensor my measured voltage is .78 volts throttle plate closed and 3.7 volts at wide open throttle. Seems to be correct parameters from my research. Thoroughly cleaned the throttle body which was really impacted with dirt. Now onto researching the O2 sensor and then the map sensor and then finally investigating the vacuum lines for leaks. Stand by, installing 5.0 motor in 4runner. Quote Link to comment Share on other sites More sharing options...
transporter Posted June 5, 2016 Author Share Posted June 5, 2016 Success... used the old Seafoam, used 1/3 can down throttle body until engine died, pour some more in, let stand 20 min, start back up, white smoke for 5 to 10 minutes... now runs like a champ! Quote Link to comment Share on other sites More sharing options...
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