Stutter ... Hesitation

[2ard]

I have a LS400 94 MK2 and having been out of country for 1 month, I've come back to the car to find some problems that have appeared out of no where !

The car fires up just fine and is okay until it reaches the normal working temp. which is halfway on the dial. The idle speed then drops to 550-600 rpm (when in P ). Before I could not feel the car running when it was on, now I can feel a little vibration, and several days ago I could hear an irregular single occurances of missfires heard as "pop" noises from the back of the car. I am going to have a look at the Air filter as I have not serviced the car since I bought it 3 months or ago and also take a look to clean the Throttle Body. What is the general concensus on using injector cleaning solutions? Has anyone done this, was it effective, is it recommended, can it to any harm ?

I also was getting a poor / sluggish / hesitant ride on the motorway specially around 55mph!

Im thinking some of the faults may be from

1) Throttle body air sensor

2) HT leads

3) Spark Plugs

4) Injectors need cleaning

Any other suggestions / ways to fix this issue would be great to hear

[ColinBarber]

Another thing to look at is the throttle position sensor.

Injector cleaners are fine if you don't use them too often or use one that is designed to be frequently used.

http://www.redlineoil.co.uk/products/fuels...temcleaners.htm

[2ard]

Im thinking of doing a service on the car, but being the first time ... does anyone know the prices for the following at all ???

Set of Spark plugs from Dealer? £££

HT leads ?

Air Filter ?

Oil filter ?

What discounts could you get if your a gold member? What will the difference be?

I need exact figures (UK sterling £).

[ColinBarber]

Give Chris Shipley a PM. He will supply those to you and if you join gold, with a discount.

[flotsam]

having been out of country for 1 month

I think leaving the car standing for a month is the biggest clue but without any further info difficult to say.

If you've taken it out for a long run it should clean out any problems that injector cleaner would do IMHO.

I don't believe that injector cleaners are that effective unless you take out your injectors and soak them overnight or something. This is just my personal, untested opinion. I can't see how a little cleaner squirted through with the fuel would be that effective.

[2ard]

Im wondering for those who own LS400 MK2z, what is the idle RPM read when the car is wormed up and in Park just before you switch off from a journey longer than say 15 minutes?

Mine is around 600 RPM and Im sure its lower than what it used to be before I left it for a month !!!

Cheers guys .... looking for some replies to this one please

[2ard]

Incase anyone is reading this far down the post, I have checked with the Tonbridge Lexus boys and I have been informed that when warm the LS400 MKII should be idling at 750, NOT 500-600 like mine at the moment. I will crack on with the throttle body this weekend and will report back

[flotsam]

Modern computer controlled idling speeds are very precise and accurate. You usually find the needle hits the same spot consistently. There must be something wrong with your car.

[2ard]

Flotsam => You gotta be right mate. I've done the throttle body check and sprayed the inside of it. I found the air filter was really filthy. I also put in the Redex injector cleaning stuff from Halfords, 99p for 50ml. I put it in on half a tank !! The car feels better, but the stutter and hesitation is there between 40MPH and 55MPH. I got prices from dealer for following, what I wanted to know though is how much can I save if I become Gold Member?

Prices from Main Dealer for LS400 MK2 are:

Air Filter: £20

Oil Filter: £10

HT Leads: £160

8 Sparks: £100

Can one of you guys with Gold Membership tell me how much you save when compared to these prices please?

Many thanks in advance

[flotsam]

You're right about Gold membership. I was wondering about it for my insurance but without a quote, there's no way I can determine whether or not it's worth going for.

[davepruce]

When I first got my '93 3 years ago, I found a stutter/hesitation at between 45 and 50 on a light/steady throttle. Anything other than that and it was unnoticeable.

It went into Lexus Canterbury and spent 2 hours on their machines, they put a new Lambda sensor in and it made a marginal difference that lasted about a month.

I've now got used to it, its no better and no worse, I've changed all the usual stuff, Plugs filters, leads etc etc and nothing makes any difference - I just live with it. (Like I live with the blown clock and the A/C screen and the fact that I have no dashboard lighting until the temp gets above 7 degrees, and no tacho needle ever!)

Its probably one of the computers, but finding which one plus buying another would probably cost more than the cars worth so............

Dave

[2ard]

Dave,

Mate let me say Im glad you posted that. Now I know Im not the only one. I have not been 100% certain if it was just me sensing it or if there actually really is a stutter going on !

Now, about your dash, for £150 or even less now that the dollar has got weaker, you can get your dash fixed mate. If you need help let me know, I live in Maidstone and have done my dash. I had issues with it, got it sent over to Jim Walker [nice chap in California USA]. I took lots of photo's when I took my dash out and I can give you a hand if you like to get yours sorted out.

Here is my E-mail if you want any further information about the dash situation: LS400@ardavan.co.uk

[mudzs]

Can one of you guys with Gold Membership tell me how much you save when compared to these prices please?

Many thanks in advance

If you use Tonbridge lexus you will save nothing as they do not accept gold .You would have to take it to another garage like bromley who i think accept it and save around 15% i think.I think i am thinking to much

[2ard]

Okay, quick update for those reading on ... I have spoken to Bromley branch, they don't give any discounts. The Owners of the franchise have decided against the discount scheme. The Croydon branch which is less that 10 miles away does it. As Mudz said, the Tonbridge office don't offer discounts either !

I had the throttle body re-examined today and it looks like it needs to come out completely and be cleaned. This will mean that the actuall throttle body which has 2 gaskets will have to be opened up, hence new ones will need to be ordered.

Anyone ever done this?