Ls400

[Jeff]

I have been running my 1991 LS400 for 3 years on L.P.G. with only occasional use of unleaded fuel when L.P.G. has run out. The engine has now developed a persistent misfire. My local Lexus dealer has diognosed a burnt/sticking valve. He says that he has had 3 others diagnosed with the same problem, all of which have been converted to L.P.G. Before looking at very expensive surgery, I am going to try running on petrol with an upper cylinder addative(redex or similar) to see if this cures the problem. If this doesn't work, does anybody know where I can get the cylinder heads renewedwith new valves etc. atg a reasonable cost? My local Lexus dealer currently charges around £80 an hour. Help!!!

P.S I live in Wales, near cardiff, but am prepared to travel a reasonable distance.

Jeff.

[ColinBarber]

There are quite a few LS400s in scrap yards. If they haven't used LPG the heads should be fine.

[Jeff]

I have been running my 1991 LS400 for 3 years on L.P.G. with only occasional use of unleaded fuel when L.P.G. has run out. The engine has now developed a persistent misfire. My local Lexus dealer has diognosed a burnt/sticking valve. He says that he has had 3 others diagnosed with the same problem, all of which have been converted to L.P.G. Before looking at very expensive surgery, I am going to try running on petrol with an upper cylinder addative(redex or similar) to see if this cures the problem. If this doesn't work, does anybody know where I can get the cylinder heads renewedwith new valves etc. atg a reasonable cost? My local Lexus dealer currently charges around £80 an hour. Help!!!

P.S  I live in Wales, near cardiff, but am prepared to travel a reasonable distance.

Jeff.

←

Thanks Colin, I am following this suggestion up. Problem is, I still need to find somewhere to have the work done by someone competent at Non-Lexus Main Dealer prices! Anyone have any suggestions?

[tangray1]

Jeff I would have to disagree with there diagnosis the majority of missfire`s are down to ignition faults . plugs ,leads ,caps and of course moisture, I to run my LS on lpg ,keep on top of these things its important with lpg, if your worried about your valves get a flash lube system there only cheap . :)