You might have to just suck it up and bring it to the dealer, (I hate saying that) they have all the special equipment to diagnose any problems you have, with your car anyway. That's why they charge so much. Any more updates, should go in your original thread.

 

I actually went to the time and trouble of posting a reply to this problem yesterday so you go and repost again,go back to your original merged thread and read,if what I wrote doesn't help I'm sorry as most of us on here are not professional mechanics so we go on our own experiences shared with others.

 

Threads merged. Please reply to your existing topic rather than creating new threads on the same content

 

thanks Dave!

 

took my 96 Lexus LS400 has 184k on it to a local shop, (wifes friend) to simply take the old plugs out put new ones in. after the new plugs were in, the car wouldnt idle right or run right, lack of power, shaking, RPM jumping up and down. the mechanic said "you got a bad plug wire". uh ok, it was fine before, anyhow, 65 dollars later new plug wires installed, same problem, he says one of the NEW plug wires is bad, wont idle right, shaking like crazy. he seems to think it is a vaccum hose that is sucking air, he has one final chance tomorrow to fix my baby before it goes to the dealership, i dont care how much it cost i want it fixed. please help with your opinions guys.
UPDATE<><> so the guy was saying it was a vaccum hose, today he calls and says BOTH of the distributor caps were cracked, they were both fine before he got it,and new ones were needed, so the new ones were installed, and the guy actually says one of the NEW caps was bad, gotta replace it tomorrow. FOR REAL??? I called toyota and they refused to service it, but insisted it was a vaccum leak, Im frantically searching for a good auto shop to have it TOWED because it wont even start now.CAR WAS TOWED to a shop specializing in foreign cars. according to the new shop the first so called mechanic, he put ford plugs in my car and then it ran bad of course, then blamed it on plug wires, then distributor caps, the new mechanic is a great compared to the other dipwad. the new mechanic say the ford plugs did something but is still searching. he says it getting good spark with the new ngk plugs, getting fire and fuel pressure. the car will start and run about three seconds then dies. he is saying the computer is shutting the fuel off, and that the cars computer isnt allowing him to communicate with his shop computer. i feel much better its in better hands but at 100 bucks an hour im nervous it did some major damage. the mechanic at the new shop specializes in foreign rides, he finally got his shop computer to connect and my car computer is showing no codes, meaning no issues, it starts for only a second and dies. he has looked for three days and hasnt found any problem. has me wondering could it be a fuse? or resetting the computer on the car? im put 230 dollars so far and wondering myself what the issue is. thanks for any opinions. the new shop normally charges 100 bucks an hour labor but isnt charging me that, guess cause they dont know what the first guy did. please provide any GOOD ideas. QUESTION, would a ECM out of another LS400 work? is it a plug up and go? or need tweeking? they look somewhat affordable, any ideas?

 

I hope he got his LS fixed but with it being a '96 I don't understand why someone (he, or anyone else) didn't just get an OBD-II code reader from an auto parts store and see what the car says the problem is since OBD-II can even tell you about individual cylinder misfires and such and a whole lot more, unlike my currently unhappy OBD-I '94 LS which got fussy 50 miles from home on thanksgiving day and tells me everything's working great when it's obvoiusly not because OBD-I is fairly clueless, but that's a whole other topic...

 

Check my old posts on my 1990 LS400. I learned the hard way. The fact you let them put Ford Plugs is amazing. Use OEM parts and do it right. Timing might be off. I bought an OBD I &II reader all it did was tell me the computer still worked. I had no codes on display. Check this site out. It was a big help. Good luck and I’ll check back.
http://www.lexls.com/tutorials/ignition/

Topher60

 

Wow, I'm so sorry that you're being put through this wringer. Honestly, given the information you've provided, you really need to take it to a Lexus specialist or a dealer. Changing plugs, wires, or a dizzy cap on a '96 LS4 is pretty darn easy, but when an awful mechanic screws things up, there's no telling what he might have jacked up to bring your car to this level of failure.

 

The guy you went to obviously doesn't know much about engines. Its obvious he touched something that is now not on right. He should go back and look at everything near the wires. My guess is he knocked off a vac. hose. After you get it resolved I'd sue him in small claims just for the aggravation.

 

The mechanic already showed what can happen when he touches it. On top of that, the mechanic was the original poster's friend. I'd rather put a blindfold on and try to fix it than take it back to that guy again.

 

We didn't get a follow-up to this.

This is one reason why to insure it goes back together right, do one plug at a time: Pull the wire, remove plug, put fresh plug in, plug wire back on. Same procedure for replacing the wires. Some people cannot discern cylinder #1 so it messes up everything there. If he unknowingly removed all that intake piping to have easier access, no telling hat has been unplugged/knocked loose.

 

My 2c, since I'm dealing with the same symptoms

I'm curious to know how your mechanic knows that the ecu is cutting fuel without codes. Id put money on that, if he could pull codes, hed see a 14 or 15, one of the ignitors isnt sending spark confirmation to the ecu, causing it to cut fuel.

If it dies after 3 seconds have your mechanic test the igf wire (y-g for # 1, y-b for #2) for a pulsed 4-6v signal to the ecu on each igniter, this is the wire the ignitor uses to send the 'fired' signal to the ecu, if it doesn't get this signal it cuts fuel to prevent the cylinders from flooding.

This can be caused by the ecu, igniter, coil, engine main relay, or wiring between any of these. Codes make it easier, but in any case your first mechanic belongs in jail. Edit: just noticed how old this thread is. Well this info should help somebody.

Mine fires, then stalls at idle. First few times it takes 2-3 minutes to stall, but once it gets to the first tick on the temp gauge, dies 1-3 seconds after cranking, and throws an ecu fuel cut due to no igf signal.

In my case, I think ive narrowed it down to the relay.

 

I had an issue when I replaced the plugs and wires in my 1991 LS400. On the left bank, the wire from the distributor to the coil was shorting out to the engine block. It cut the whole left bank out, making the catalytic converter glow red hot. I had to put the original wire back in to fix it.

I used non-OEM wires, which are all slightly longer than OEM, and they are not as well insulated. Lesson learned.