Some engines have had the problem of the crankshaft pulley bolt coming loose. This will make a rattling noise as the engine idles. Our technicians tell us that the pulley bolt should have a thread locker applied and then retorqued.
Problems for specific Toyota models:
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Most reported Toyota problems
Occasionally, the mass air flow sensor can go lean and set a code P0170 for fuel system lean. This in not an oxygen sensor problem. If there are no vacuum leaks, the mass air flow sensor may need to be replaced. Our technicians remind us to use a factory part because the aftermarket rebuilds are very inconsistent.
At higher mileages, an anti-lock brake system wheel speed sensor may wear out and illuminate the ABS warning light. It is recommended to replace the sensor with a factory part and be sure to clean all rust and debris from the mounting area because the mounting distance is critical. Failure to do so may result in the new sensor setting false trouble codes.
The Throttle Position Sensor can get out of adjustment due to wear in the throttle body or due to carbon build up. This will cause the idle timing to advance more than 30 degrees which will cause very high HC and NOx emissions. Conversely, the Throttle Position Sensors can wear out and not properly advance the timing which causes a lack of power and poor fuel economy.
The ignition coil inside the distributor may fail. Our technicians tell us this may result in a hesitation on acceleration, especially when the vehicle is warming up on cold, rainy days. The pickup coils inside the distributor can also fail and cause a no-start condition. There have also been some failures of the radio noise suppressors inside the distributors, which can short out. Our technicians recommend replacing the whole distributor with a complete, genuine Toyota distributor if any of its components fail.
The AC Expansion Valve may develop a very slow leak or allow too much refrigerant flow which reduces cooling. Our technicians tell us that Toyota makes an updated expansion valve to resolve these problems if and when they occur.
At higher mileages (125,000+) the mass air flow sensors may cause the vehicle to idle rough, run rich and even stall. Our technicians recommended to replace the mass air flow sensor with a factory unit because the aftermarket units have very mixed results.
At higher mileages (125,000+) the Engine Coolant Temperature Sensor may intermittently stop working, especially when the vehicle is fully warmed up. This can cause the engine to stall unexpectedly.