Regardless of what the mechanic said, the sender is a common and cheap part to change in this situation. It's the cheapest part in the system. That said, the only way to know if you have an indication problem vs an oil starvation problem is to remove the sensor and connect a direct reading oil pressure gauge in it's place. This will tell you the true pressure in the system. If it then reads the correct pressure you start with a new sender. If it reads low then you have a bad pump or an oil channel or galley is blocked internal to the engine. It's a simple system with few options to repair.
BTW - Why did the mechanic do a flush? Did he pull the valve covers and see the sludge or just surmise there was sludge. Flushes are a risky proposition.
Last edited by RIP; 01-14-2009 at 02:35 PM.
******** We took the time to answer your post. Please give us some time and post the fix. You'll help hundreds. ********
**** Follow all prescribed safety procedures before attempting any repairs. If in doubt, refer to a maintenance manual. ****
96 Gr Caravan LE 3.8, 214K miles
07 Fusion / 06 RAV 4 / 06 Accord