My 1999 lexus Rx300 has misfires. we recently replaced all sparkplugs and it still continues. we are getting reading codes of P 0300, 0301,0303,0305 plus p1305,1315 and 1325. My local part department seems to think it my be a control module problem. what do you think would still cause misfires after a tune up.?

SOURCE: ? to Replace Timing belt on 2000 Lexus Rx300 with 57,000 miles.

If it is running perfectly I wouldn't think that you would need to replace the timing belt. You shouldn't need to replace that until 100,000-120,000 miles. I would definitely hold off until now unless you have start having some timing problems. Let me know if you have any other questions. Thanks for rating my response and for using FixYa!

SOURCE: High RPMs

yes its related to knock sensor because car is running rich in fuel, and car runs of on safe mode, so overdrive will be off. have you and a friend replace it. remove intake assembly, then intake manifold, but first remove your anifreeze from radiator, trust me you want to remove antifreeze! their are brackets by the fire wall to hold down the manifold, thats the hard part is taking it off and putting that on since not to much space to work on it. on the block you'll see the two knock sensors, has 2 wires each, knock sensors cost between 150- 200 a piece, still cheaper than dealership putting it on. also buy some liquid gasket because you will need that. after putting it all back together reset the ecu and you should be fine,

SOURCE: 2003 Chevy Venture misfiring

The injector is a good possibility, although you should check for spark in the wire first, as the electrical is the weakest link in the system. Put a spare plug in the end of the wire with the plug resting on metal, then have someone crank the van to see if you have spark that far, test and replace spark plug, (do not get shocked!) then look into a new injector or a good cleaning.

SOURCE: how to tune up the lexus rx300 can't locate the

This is a lenghty job!! You would have to remove the plastic engine cover to locate the plugs (cover that has the lexus symbol). There are 3 coils(black squarish units) on the front head and another three in the rear head. You must remove these to access the sprakplugs. Front is very easy!! The rear is difficult, you would have to remove the intake(special tools are needed) to access the rear coils and sparkplugs. hopefully this helps

SOURCE: I have 3 codes 1) P0500

The PO125 is an indication of an engine running too cold-as if the thermostat were stuck open.For some reason it often sets with the PO1135 even when the engine runs at normal temp.A scan tool will indicate exactly how hot the engine is,don't trust the dash gauge. The PO1135 is a heater circuit fault in the bank1 sensor1 air fuel ratio sensor or oxygen sensor. Bank 1 is the REAR bank on this car...that O2 sensor is not much fun.PO500 is a vehicle speed sensor fault-does the speedo work correctly?it is located in the transmission near the back of the case. once again the scan tool will read vehicle speed and can aid in further diagnosis.