Gs300 Mk2 '98 R Niggles

[Darrenw]

Hello All,

Ive just bought a '98 R mk2 GS300. 110,000 miles. AG LPG system fitted. Its basically a great car and i cant believe the level of comfort and gadgets. It has a couple of niggles though that id like to get sorted. Ive tried searching but not seen solution yet.

At about 60mph i get a judder that goes off if i lift off accelerator, bit like a misfire. Once past 65 it goes off and smoothness is restored. Tickover with aircon off is about 500rpm. Aircon on about 600 ish. Seems rather low. Pulling up to junction and tickover drops a lot further making the ignition lights flicker on. Occasionally the car stalls (only when warmed up, when cold tickover is higher as would be expected).

Happens on gas and petrol. Car basically runs well on both. Im planning changing the plugs, air filter and cleaning the throttle body. Should this cure it?

Is there anything else to check?

I seem to recall some cars have an idle control valve that can get dirty.

Any vacuum pipes on these cars?

What plugs should i get (Eurocarparts list several Denso options but little description, just a range of prices £7 - £11 ish per plug)?

Is tickover only settable via ECU? I have a mate with Snap-on scanner, im hoping that will do it.

Thanks all for help. Im in North East close to Darlington if there are any experts in the area. (Petrol tank started to leak at weekend too but im hoping ive sorted that).

Cheers,

Darren.

[fildigger]

Well, first of all give the car a Full service by a competent mechanic (indie) or at Lexus, Then Get the LPG system thoroughly checked out and Overhauled (personally, having had experience of these systems, they can be temperemental, suffer from bad initial installation and lack regular servicing, also throw in the fact that some cars are more suited to LPG than others and you have a recipe for poor running!! and potential Big bills for engine failure/damage!!)........I wouldn't have an LPG system on the 2JZ-Ge engine, My Opinion!...It isn't that bad on economy for the performance you get!

Good Luck.

[Darrenw]

Thanks fildigger.

I can do the service myself (qualified engineer and part time car builder). Mostly im running petrol due to rather small LPG tank and the hours im working. The niggles im reporting are mainly on petrol.

Anyone else had similar niggles?

Ive noticed the car looks like its had a replacement throttle body - it has the white paint marks typical of parts bought from breakers. Is it possible the throttle sensor could be set for the last car and need a tweak?

[fildigger]

Ok, So the issue is while running on Petrol!

Well, you are possibly right with the sensor theory!....Mass air flow sensor being being the typical culprit!

...However, it is prudent to get the car hooked up to the correct diagnostic equipment, without this you could running around in circles & replacing all manner of costly items without getting to the real root cause of the problem!

An unfortunate (or should i say Fortunate?) situation with all modern machinery is that Your 'brain' is no match for the ECU's brain !!.........It Knows, you don't !!!!!!! (usually)

[Darrenw]

Fixed the niggles. There was a part of the air intake that wasnt fastened up (after MAF). Cable tied it and it runs very smoothly indeed. The car is an absolute pleasure, unbelieveable for the age and doing equivalent of 40mpg on gas.

Shame im going to sell it!