headylinton
New Member
@Wranglerfix I'm have a hell of a time chasing down some problems with my 97 4.0 swapped into a 98 2.5 TJ. I heard you are the guy to talk to. I am stuck, I recently did a frame off refresh while swapping a 97 4.0 onto a 98 2.5 frame because I already had everything here. I got it about buttoned up but I'm chasing a gremlin. The engine runs great, starts right up, maybe some slight missing, but no codes for the most part. When I take off to drive it drives great, I get about a mile down the road and it starts surging and bucking usually after slowing down and speeding back up. The weird thing is that I can put it in neutral while rolling then kill the engine and restart it, then it's instantly fine for another mile. I've replaced most of the sensors even got the ntk upstream O2 sensor, the downstream 02 sensor is running over 1.0 and the shrtftb1s2 is 99.2. My live data is reading an average of 18 on the spark advance, 230psi on the map, and about 40-50psi oil pressure at idle all are high. The only code I get sometimes is p0171 system too lean bank 1 it's not consistent tho it's after driving it and leaving it running for a really long time restarting it to get back home. I am still throwing parts at it and I great it might be the PCM, I still have the PCM from the 98 also but it needs to be reprogrammed in order to try it because it was 2.5. I can't find a vacuum leak anywhere. I'm at my wits end and hopefully at the finish line of a year long project. I've crawled all of the forums and can't figure it out. Any help would be loved!
