Re: PCM Tuning 1999 4.0 liter WJ
SCT is available for the 4.0 crowd. I sold my first tuner to a guy with a 4.6 stroker motor in a WJ. I referred him to Josh Bryant. I spoke with the buyer several months later, and he said his experience with Josh was nothing short of excellent. I can also recommend Sean Powell, as I have experience with both tuners. Josh is no longer the tuner for Air Ram but the new guy, Chris, is pretty smart with this stuff. I would strongly recommend going the SCT route over "mail-order flash" tuners.
Does it still throw codes or have they not come back? You should, before seeking tuning, verify that there isn't an actual sensor issue or some other mechanical shortcoming like a vacuum leak.
Due to my workload, please do not PM me as I do not regularly check my PMs. Thank you :)