Pontiac Repair: oil pressure, oil pressure sender, balance shaft

Question
Car is a 1999 Sunfire GT, 2.4 ltr., auto. trans. Has approx. 168,000 km (105,000 miles).Oil light comes on intermitently. I changed the oil pressure sender but it did not help. I had the oil pressure checked-only 5 psi at idle, 8 psi at 2000 rpm. The engine is running smooth and is not knocking (yet). Is changing the oil pump the answer?
Thanks

Answer
Hi Derek:
those Pressures are too low. I'm old skewl and like to see 10 PSI for every 1,000 rpm's Not every engine will meet those specs but it's a good rule of thumb. Chances are that the engine is getting tired and need to be freshened up. The oil pumps usually do not go bad on those engines. if the engine has not been maintained it could be a sluge issue on the oil pump pick up. the oil pump is an odd set up on that car it's in the middle of the engine on the counter balance shaft housing. I'm thinking you need to have it take out and torn donw for exploritory surgery to see what it worn out. if this just started happening you may be able to get away with just a fresh set of bearings but if you keep driving it your going to have upper engine issues going on here like cam shaft housing worn out. That gets expensice in a HURRY! In a pinch you could always use a heavier weight oil like a 15w40 diesel oil until you can get it looked at or the $ to get it fixed right. good luck :)