Mom's 94 Lexus Posted August 31, 2008 Share Posted August 31, 2008 93 LS400 (75-80,000 miles) driving normal at highway speeds, hickuped once, then began running rough, very rich (stinks, one or both cats hot, and some black smoke out tailpipe when accellerating), barely idles, and the check engine light is on. I followed the proceedure carefully for reading codes (not my first rodeo) but get no blinks at all - no continuous blinking indicating no codes and nothing indicating a particular code. My first thought was the TB but it was replaced less than 15000 miles ago by the dealer. Here is where it gets odd - once this condition presented, the car would not put itself into 1st gear. I can manually shift to 1st, but it was trying to leave from a stop in 2nd or 3rd. Car did same thing yesterday pulling out of a gas station (fill up), after a fairly long in-town drive in hot weather. CEL was on. Wife wisely left car in parking lot and we went back (to the soccer tournament) this am. I checked codes and got the steady blink indicating no codes (I can't even get that now). One confusing issue was a courtesy light was on all night so the battery was amost dead, had to jump it off. But it ran fine until the repeat event coming home from the tournament. While I realise this could be many things, I find the inability to read the codes odd. Also I hope the sudden onset might be a big clue for someone out there. Thanks in advance :o Quote Link to comment Share on other sites More sharing options...
python Posted August 31, 2008 Share Posted August 31, 2008 computer maybe? Quote Link to comment Share on other sites More sharing options...
Bali26 Posted August 31, 2008 Share Posted August 31, 2008 Black smoke and rich sounds like unburnt fuel, and sudden power loss sounds like it might be an ignition problem. For example one coil going out and car is running on 4 cylinders. Quote Link to comment Share on other sites More sharing options...
python Posted September 1, 2008 Share Posted September 1, 2008 on an obd 1 a bad coil wont throw a code and if it did it wouldnt effect the ability to check the code Quote Link to comment Share on other sites More sharing options...
Mom's 94 Lexus Posted September 1, 2008 Author Share Posted September 1, 2008 on an obd 1 a bad coil wont throw a code and if it did it wouldnt effect the ability to check the code The coil sounds very possible - thought maybe after it cooled it worked again until finally giving up - probably an internal insulation failure. While the CEL was on, I didn't get a code the first time - normal steady blinks. Now I can't get that - maybe I did something - I did pull the 20 amp fuse to clear the codes after the second time it happend. We have a great Volvo shop up the street with an award winning diagnostic tech. I'll risk a couple bills on a chance with them. I just don't have time to experiment right now. Thanks for the suggestions - I'll share with them. Quote Link to comment Share on other sites More sharing options...
93ls400walt Posted September 1, 2008 Share Posted September 1, 2008 The transmission issue make me think of the wire in the trunk problem. The wire harness on the drivers side trunk hinge, one or more wires pull apart or frays causing a short. There is more detailed info on this if you do a form search. Otherwise I vote for the coil. Apparently the driver side coil goes out primarily, being lower and subject to more heat. Quote Link to comment Share on other sites More sharing options...
killerFatty Posted September 2, 2008 Share Posted September 2, 2008 l would definetly put my money on the coil. Quote Link to comment Share on other sites More sharing options...
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