My Is200 Stops Working Every Other Sat Wtf? Help

[john_boy]

hi peeps 1st im getting a squealing noise from somewhere starts when im doing over 30 and stops when i slow down to about 20, other than that theres nothing that happens to set it off its bin to my local mechanic a few times bt he carnt find any thing rubbing on wheels pads or dics, its driving me mad it can be a quietish noise bt then can sound like a firwork tacking off any ideas? The second moast strange this is one saterday id bin driving about turned the car off for a bit went to turn it back on and it started up but as soon as it starts the revs just drop and the engine cuts out, it seems like its starved of fule but its not, it then takes abou half an hour for it to start and stay ticking over even tho it still sounds like its not got enough fule, bt this has sappned three times now but its every other saterday i just carnt c the logic because other than the horid squealing it as good as gold n never misses a beat im quite reluctant to take it to lexus coz itf far away and exspencive lol. any ideas on either problem would be most appreciated thanks