Engine Missfire

[93ls400walt]

Hello to everyone. I am a new member with my first Lexus. A 1993 LS 400 bought through EBAY in Florida. As you know this is a wonderfull automobile. But soon after I received the car it developed a miifire at low speed then at idle and finally at freeway speeds. Jerking on the slightest acceleration. Esp. on an incline. Could barely acheive 40 MPH on a hill. The missing was intermittent but very frequent.

I had some great advice from a Forum member as to where to start. I started with a tune up. I found massive amounts of corrosion on 2 plugs and inside the right bank coil wire and dist. cap terminal junction. Replaced everything and my "new " LS 400 is running fantastic now.

I just wanted to pass this info. on to the forum. And say thank you to all who post. You advice was invaluable to me. walt

[vixlex]

Hello to everyone. I am a new member with my first Lexus. A 1993 LS 400 bought through EBAY in Florida. As you know this is a wonderfull automobile. But soon after I received the car it developed a miifire at low speed then at idle and finally at freeway speeds. Jerking on the slightest acceleration. Esp. on an incline. Could barely acheive 40 MPH on a hill. The missing was intermittent but very frequent.

I had some great advice from a Forum member as to where to start. I started with a tune up. I found massive amounts of corrosion on 2 plugs and inside the right bank coil wire and dist. cap terminal junction. Replaced everything and my "new " LS 400 is running fantastic now.

I just wanted to pass this info. on to the forum. And say thank you to all who post. You advice was invaluable to me. walt

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hi, i am a honda mechanic, and my dad bought a 92 ls 400, the ls started doing all the same symptoms as you described, i changed all plugs, wires , cap & rotor (2), fuel filter. still did the same thing. then i replaced both coils, still doing the same thing

[SKperformance]

So is the misfire on idle or a certain rpm?

[vixlex]

So is the misfire on idle or a certain rpm?

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thanks for replying, yes just sitting at a light it keeps missing, and when you

are accelerating up hill it will start missing-problem happens once vehicle warms up.

[SKperformance]

You may have carbon build up what grade gas do you use?

[cardona6569]

Hello to everyone. I am a new member with my first Lexus. A 1993 LS 400 bought through EBAY in Florida. As you know this is a wonderfull automobile. But soon after I received the car it developed a miifire at low speed then at idle and finally at freeway speeds. Jerking on the slightest acceleration. Esp. on an incline. Could barely acheive 40 MPH on a hill. The missing was intermittent but very frequent.

I had some great advice from a Forum member as to where to start. I started with a tune up. I found massive amounts of corrosion on 2 plugs and inside the right bank coil wire and dist. cap terminal junction. Replaced everything and my "new " LS 400 is running fantastic now.

I just wanted to pass this info. on to the forum. And say thank you to all who post. You advice was invaluable to me. walt

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Hello: Since you have the car running good, If you have not, replace the air filter, or clean it if it is not ultra dirty, clean the Throtle Body of carbon build up, that should be really bad in the back part of it, tutorials in the site available. Also another good one to do is to clean the Maf Sensor. Research in the forums the information is there. You can also log in into the UK, they have good info there also. I suggest to both of you, the one without problems and the one with problems. It is good preventive maintenance. Walt if you found your plugs very dirty, imagine what you are going to find inside the TB. I have done to mine all I have said here and is running like new!

C. PR

[93ls400walt]

Hello to everyone. I am a new member with my first Lexus. A 1993 LS 400 bought through EBAY in Florida. As you know this is a wonderfull automobile. But soon after I received the car it developed a miifire at low speed then at idle and finally at freeway speeds. Jerking on the slightest acceleration. Esp. on an incline. Could barely acheive 40 MPH on a hill. The missing was intermittent but very frequent.

I had some great advice from a Forum member as to where to start. I started with a tune up. I found massive amounts of corrosion on 2 plugs and inside the right bank coil wire and dist. cap terminal junction. Replaced everything and my "new " LS 400 is running fantastic now.

I just wanted to pass this info. on to the forum. And say thank you to all who post. You advice was invaluable to me. walt

←

Hello: Since you have the car running good, If you have not, replace the air filter, or clean it if it is not ultra dirty, clean the Throtle Body of carbon build up, that should be really bad in the back part of it, tutorials in the site available. Also another good one to do is to clean the Maf Sensor. Research in the forums the information is there. You can also log in into the UK, they have good info there also. I suggest to both of you, the one without problems and the one with problems. It is good preventive maintenance. Walt if you found your plugs very dirty, imagine what you are going to find inside the TB. I have done to mine all I have said here and is running like new!

C. PR

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thanks for the info. I have not yet cleaned the throttle body. I was just searching the forum for info on cleaning the T.b. and saw the replies to my post. Will also look at the MAF sensor. I still get occ. very minor rough idle. I have also ran Sea Foam three times. Plan a new fuel filter. Air filter was in good condition. I've no other advise for my friend 93ls400 with 250,000 miles. But I do wish you luck. And look forward to your post when this is resolved. E-mail if you like w.desha@insightbb.com