Niagara Gazette — BERT FROM SAN DIMAS, MEXICO: I own a ‘04 Toyota Highlander 4 cylinder, 82,000 miles. My local shop sent me a notice to have the EFI throttle body serviced. What is an EFI throttle body and how often does it need service? The vehicle is running fine, so I wonder if this service is really necessary at this time?
TOM: EFI stands for Electronic Fuel Injection and Throttle Body is the term for a component in the injection system where air is taken into the engine. Fuel injection systems require cleaning at regular intervals, every 35 - 40 thousand miles. This process is necessary because varnish deposits, dirt, and carbon build up on the end of the injector nozzles, inside fuel rails, inside intake plenums, on the tops of the pistons, and inside the cylinder heads and valves. The cleaning process involves injecting an industrial grade carbon cleaner into the system, and then letting it sit to liquefy any carbon buildup in the engine. A professional cleaning of the injection system and upper regions of the engine usually results in increased performance and better fuel mileage.
RUTHANN FROM EAST AURORA: I own a ‘91 Chevy S10 pickup, 4-cylinder. The oil gauge goes spastic at times. Also, the pressure runs low on the gauge when it isn’t acting up. Finally, nearly every time the vehicle turns left I hear this loud popping, clunking sound. Any idea what that could be?
TOM: In regards to the spastic oil pressure reading, run an oil pressure test with a mechanical gauge to confirm actual oil pressure. If it is low, the engine will have to be disassembled for proper inspection of the parts that relate to oil pressure. If the oil pressure is okay, then check for a bad sending unit or wiring to the unit (this is most likely the cause of the erratic readings). The popping sound could be a bad ball joint, control arm bushing shock, or some other suspension part. Get the truck up in the air for a suspension inspection. Success to you.