Larry Yarbrough

Hello all, I am in dire need of help and its driving me crazy literally. A month ago I was driving and my check engine light came on and my O/D light started flashing. I then noticed my rpms went up to 3000 only at 60 mph!! The engine would start reving up to 6000rpms out of the blue!!! Then, I took it to advance and had them test it..They got p050 and p0720 codes. The guy at advance siad replace the speed sensor on the tranny. So i took it to pepboys and they replaced it...nothing changed..now noticed the engine started cutting off at idle every couple of hours.. I then took it to the dealership. They advised I needed a new ecm and dash cluster. I couldnt afford the $2000 they were asking so i went to ebay. I bought a used dash cluster and ecm. I noticed a difference this time, the check engine light went out by itself then the od light went out. I could actually get up to 80 mph now , got the power back........ Today, the check engine light comes back on, rpms back up too. Any Lexus experts here have any ideas?? I am not ready to give her up but cant afford $2000... thanks so much LarryLexus larryyarb@bellsouth.net