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Steven Scott

1990 Lexus Ls 400 Intermittent Misfire

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Hi,

Two months ago, my 1990 Lexus Ls400 had a new power steering pump fitted, was serviced and had the spark plugs changed. Since then it has developed an intermittant misfire and has been back and forth to the garage numerous times. I drive it away and it seems fine and can remain fine for a whole week, then the problem occurs again; usually after having just started the car and driving it for a couple of minutes. One time I was completely unable to start the car and had it towed in to the dealer.

It looks like the dealer has run out of ideas. Since this problem started, I have had a new alternator (damaged by the power steering leak no doubt), new battery, new leads, rotor arms and distributor caps. None have succeeded in solving the problem. I really get the idea that when they replaced the power steering pump they did something wrong to cause this problem, but I can't get a lot of sense out of them.

Any ideas would be greatly appreciated as this car means a lot to me.

Steven

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Hi,

Two months ago, my 1990 Lexus Ls400 had a new power steering pump fitted, was serviced and had the spark plugs changed. Since then it has developed an intermittant misfire and has been back and forth to the garage numerous times. I drive it away and it seems fine and can remain fine for a whole week, then the problem occurs again; usually after having just started the car and driving it for a couple of minutes. One time I was completely unable to start the car and had it towed in to the dealer.

It looks like the dealer has run out of ideas. Since this problem started, I have had a new alternator (damaged by the power steering leak no doubt), new battery, new leads, rotor arms and distributor caps. None have succeeded in solving the problem. I really get the idea that when they replaced the power steering pump they did something wrong to cause this problem, but I can't get a lot of sense out of them.

Any ideas would be greatly appreciated as this car means a lot to me.

Steven

check engine light coming on

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did you check coils?

misfire can be due either incorrect timing, bad coils, rotors, rotor caps cables or spark plugs, since you checked rotors, rotor caps, check coils and spark plugs.

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did you check coils?

misfire can be due either incorrect timing, bad coils, rotors, rotor caps cables or spark plugs, since you checked rotors, rotor caps, check coils and spark plugs.

MAKE SURE YOURS IS EXACTLY LIKE THE DIAGRAM.

You owe me a beer :cheers:

PLUG_WIRES_V_8.pdf

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did you check coils?

misfire can be due either incorrect timing, bad coils, rotors, rotor caps cables or spark plugs, since you checked rotors, rotor caps, check coils and spark plugs.

MAKE SURE YOURS IS EXACTLY LIKE THE DIAGRAM.

You owe me a beer :cheers:

i have done a full tune up on my 92......make sure u get dealer wires, they come with everything, there is a plastic wire holding mount that goes in each valve cover as well as up front and they are already set up and put in order, no messing around just snap them into place! you buy after market crap u r asking for trouble

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did you check coils?

misfire can be due either incorrect timing, bad coils, rotors, rotor caps cables or spark plugs, since you checked rotors, rotor caps, check coils and spark plugs.

MAKE SURE YOURS IS EXACTLY LIKE THE DIAGRAM.

You owe me a beer :cheers:

i have done a full tune up on my 92......make sure u get dealer wires, they come with everything, there is a plastic wire holding mount that goes in each valve cover as well as up front and they are already set up and put in order, no messing around just snap them into place! you buy after market crap u r asking for trouble

Where is my beer? :lol::lol::lol:

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did you check coils?

misfire can be due either incorrect timing, bad coils, rotors, rotor caps cables or spark plugs, since you checked rotors, rotor caps, check coils and spark plugs.

MAKE SURE YOURS IS EXACTLY LIKE THE DIAGRAM.

You owe me a beer :cheers:

i have done a full tune up on my 92......make sure u get dealer wires, they come with everything, there is a plastic wire holding mount that goes in each valve cover as well as up front and they are already set up and put in order, no messing around just snap them into place! you buy after market crap u r asking for trouble

Where is my beer? :lol::lol::lol:

Due to the festivities I have not been able to sort this out. The dealer replaced the plugs, they were supposed to be the proper ones. I think I need to take it to someone else.

Don't worry, I'll buy you a few crates of beer if we sort this one out. Hopefully early next week. Is it the bad connection in the plugs causing my symptoms? I get the fact that if it is not wired correctly, there will be trouble, but don't really understand the intermittent nature of the problem. Thanks for your replies. The dealer also reckoned they checked the coils and the engine warning light of an electrical fault hasn't come on. Steven :cheers::cheers::cheers::cheers::cheers:

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Hi,

Since you are having the misfire problems after the plug, wires, cap (ignition) system replacement, I am more likely to believe that the wires were improperly installed.

Generally, if plug wires are too close together, they will cause electro-magnetic interference with each other and will throw off your timing (hence, resulting in misfires, etc..) I wanna guess that the wire installation is the culprit. Which is why another member attached the pdf wiring diagram - it has to be exact as he says.

Nonetheless, I would recommend taking your LS to another dealership that is more competent - although you would be paying more money(since it does require a bit of labor to get to the plugs). I am shocked that they messed it up - a Lexus dealership should not be making that mistake! I'm sure you paid alot of money having that work done and they should fix it at no additional cost! But, you would be taking another chance of an incompetent service.

Hope you find out the solution soon,

TEAMER

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