juliusj6 Posted June 6, 2003 Share Posted June 6, 2003 Anyone please help. I have a 1995 LS400 with 90,000 miles. I bought it used wit 88,000 miles. It is now out of warranty. I am having a problem with the engine shutting off randomly. I'll drive about 30-40 miles, and when I'm coming to a stop, the RPM's drop to a crawl and the engine shuts down. It will immediately restart and proceed as normal. It has done this on the very first day that I purchased the Lexus, but I thought it may have been cheap gas or needing a tune up! I have replaced the following: Spark Plugs Plug wires PCV Timing belt Serpintine belt Synthetic oil I use 93 octane fuel and I have checked the air filter. I have had the car checked for codes and no codes were found. The check engine light does not come on. If there is anyone who can give me an idea of what to check next, I am grateful. Thanks Quote Link to comment Share on other sites More sharing options...
AWJ Posted June 17, 2003 Share Posted June 17, 2003 The fuel pump control unit. Try to bypass it and run high voltage mode. If your stalling stops, then that is your problem. Check fuel filter as well. Quote Link to comment Share on other sites More sharing options...
hughes369 Posted July 14, 2008 Share Posted July 14, 2008 Where is the Fuel Pump Control Unit? MY car is a 1992 LS400, i think mine is going south too. Relay checked fine. Pump checked fine. It runs then shuts off, starts right back up and runs, and shuts off. You get the idea. Thanks for any help. THE SNAKE Quote Link to comment Share on other sites More sharing options...
1990LS400 Posted July 15, 2008 Share Posted July 15, 2008 As I have noted in numerous previous threads, I have had this same problem happen about every three to five years over the eighteen plus years I have been driving LS400s - first a 1990 and now a 2000. Each time it has been a bad battery - a broken electrical connection between battery cells that randomly separates and then reconnects.. I no longer bother to have the battery tested but head immediately to a store to buy a new one -- a new battery has always fixed the problem on my cars. But, of course, this is not the only thing that can cause an LS400 engine to die. Quote Link to comment Share on other sites More sharing options...
Alexander the o.k. Posted July 15, 2008 Share Posted July 15, 2008 An engine of the caliber and refinement of the 1ufe does not just shut down. There is an electrical problem somewhere. A well known design flaw has been noted--- It is the" trunk hinge wiring harness " issue. I know it well, as I was a, let's say, victim of same. Search that term. It is an easy fix and it will cost you nothing to repair, if indeed that is the problem. "This may seem arbitrary, but I may have an answer for you. This same type of problem happened to me about a year ago. This smooth world class car started balking, cutting out, lurching, and seemed ready for the junk yard. It happened all of a sudden. No warning. I thought the engine was toast. Now it's smooth as silk w/ 255,000 miles on it. Open the trunk. On the left side you will see a wire harness on the left hinge. After repeated openings and closings the wires inside that harness become fatigued and frayed. Then they start shorting out. Then your ECU starts getting bad input. Then your air/ fuel ratio goes to hell, then you have intermittant spark. Then sputtering, stalling, and everything you describe. This is a design flaw and lexus knows it. In short ( ;) ), if this describes your problem, then strip down the harness, untwist all the wires, re-connect, then re-tape with duct tape. Make sure to leave off the bracket that ensures tension on the harness. Just let it swing free and loose. In my case, problem solved, and no spending thousands of dollars in diagnostics, parts, and tech snafus. I am 95% sure this is the answer. Best of all, it's free! Good luck... " http://us.lexusownersclub.com/forums/index...hinge&st=15 I've noticed while searching old posts, that almost everyone who screamed for help, for a similar prob, stopped posting after the above reply. That is NOT conducive to learning and helping others. If this reply corrects your problem, then please say so. Quote Link to comment Share on other sites More sharing options...
nc211 Posted July 15, 2008 Share Posted July 15, 2008 Engine Computer....ECM/ECU, which ever you want to call it. This is a notorious problem for the 95-97 series. If you run a search for "Jim Walker" or "ECM" "Stalling", you'll see some threads about it. If you're driving for a while, say on the freeway, hit the exit ramp and the car stalls, but immediately starts again and is fine.....it's the computer. I wouldn't be suprised if you also have a slight bucking sensation when gently cruising at about 40-45mph and gently take your foot off the gas too... That's also a probelm with the computer, it's called off-throttle-shock, search for those words and you'll see more info... EDIT: Sory, Jim Walker is for the dash lights going dark... Quote Link to comment Share on other sites More sharing options...
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