Car: 1990 LS400 with TC Miles: 236,XXX Dash lights: CEL (right side o2) and TRAC OFF stays on (computer control malfunction) Amb temp when problem: 80-85 degrees Problem: Under more than 5% throttle or so the car "bucks" or hesitates. Also noticed the eng cooling fan only operates when I give the engine throttle in Park and comes on proportionate to the amount of throttle I give it. maybe in Drive (cant hear it while Im driving) Where do I start diagnosing? The full filler cap gasket is bad - hisses when I unscrew it, can this have anything to do with the problem? I guess I will replace it anyway. It has a newer alternator but I just read the rectifier could be fused causing problems if the guy that put it in screwed it up? I am taking it to a friends tonight who is a very experienced tech, I guess we will figure something out, just wanted to see if you "senior" members have experienced this problem and could point me in the right direction. BTW- Not to start my relationship with this forum off on the wrong foot, but I came from S2ki (owned one) and there are some VERY detailed FAQ and DIY stickies in the "under the hood" section of their boards. Stuff that would help you diagnose issues and a terrific culmination of "common problems". I am yet to find anything other than Prospective buyers stickies on this site. You gotta figure a guy buying a 10-20 year old Lexus is going to plan on getting his hands dirty considering the cost of labor at a stealership? Thx for reading.
Hello all, as of 2 weeks ago I am the proud owner of a black/tan 1990 LS400. It is rough but the mechanicals and driveline are smooth even with 236,000 miles on the analog odo! I have driven several various UCF's over the years and have some life and death stories which I will share at some point in time on here. First though, I have questions. I bridged the CEL and TRAC OFF codes and the CEL=bad o2 sensor on the right bank (no biggie) but the TRAC OFF came back as a computer control malfunction? Any insight on how to get the TC working again? The TRAC light is not on, only the TRAC OFF on the bottom of the guage cluster. Things I have discovered: There is NO CABIN AIR FILTER on 90-92 (UCF10 V1) LS400's FYI. I was a little bummed by that :( There is NO LIMITED SLIP DIFFERENTIAL in 1990 LS400's, is there one in later years? After pulling the pass door apart to fix a broken handle I discovered that the Nakamichi speakers all have one amplifier per speaker, similar to BOSE factory audio, is this correct? I noticed the 4" (blown) door speaker in mine is surrounded by black plastic which looked to be an amplifier? Can you guess how much I paid for this car ;) ?