78 308 Idle

Normal oil pressure following a cold start up would be in the 85 lbs area. The problem is that the oil pressure senders are notorious for being bad/wrong. So the first thing to consider is that you are looking at what the gauge says more than what the pressure really is. Try a new sender before getting concerned. Its the big (1 1/2 inches in diameter or so, just under the oil filter. It has one wire running to it.)

Regarding the idle, have you eliminated the possibility of the pedal and throttle pedal cable being the cause? You might want to throttle the engine up from the engine compartment and letting it drop to idle with and without the cable connected just to eliminate the easy stuff.

Best wishes.

 

I have a 78' 308 GTS and had the same problem even though the carburetors are in next to new condition (rebuild by Bob Wallace in Phoenix). A couple of years ago I finally figured out the issue. The idle mixture was too lean. My jets are stock or very close to stock, and I run the idle mixture 4 turns out. I've tried to adjust it to the recommended starting point of 3 turns out.....but I always get the problem you are describing. I would try turning the mixture out (rich) a half a turn and see how that works. If it is still an issue go another half turn. This worked wonders for me.....idles right down as you would expect. Good luck.

Jim

 

oil pressure should be 78psi to, hum... I think 92psi at 6,000 rpm and the oil temp at 210. If your oil pressure it low, check for the following things... low oil, and fuel in the oil, or if the oil hasn't been changed in a while and has a lot of miles on it, it will thin out and oil pressure will read low.