I have a 305 TBI and a T-5 tranny that idles around 1-1200 rpm's. When I bought the car the guy told me it was normal and had always idled around there (I didn't know any better at the time). But I'm 99% sure thats higher than it should be can anyone give me a ball park of where I should be?

 

Should be idling around 600 rpm. Check for vacuum leaks maybe.

 

is that what your tach reads, or are you scanning?

my tach is so far off, it shows 1500rpm at idle, WinALDL shows 650

 

Its what the tach shows, I've got a laptop and WINALDL installed on it but apparently I'm too dumb to build the cable. But it sometimes goes down to around 600 and I can feel the difference, its definitly higher than it should be.

 

Little known fact, at least I think it works like this. Check water temp when idling fast. Should have a 192 degree thermostat I think, and if someone installs a 180 or lower it will idle faster than normal. Get a good infared thermometer or an ECM scanner and read temp while watching idle speed, might see the idle drop three hundred rpms from 180 to 190 degrees. As temp goes up rpm goes down. Seen this before, maybe not in your case?

 

yes that is a possibility, but it goes off the coolent temp, and IIRC the stock computer goes into closed loop at like 165* so even with a 180* you should ok, and get into closed loop, with a 160* stat, you won't get into closed loop, but at 160*, you SHOULD get out of the high idle routine.

 

My highest stock commanded in-drive idle is 850rpm, and that's below freezing. Starts ramping down at 44*C (111.2*F), to a low of 575rpm at 104*C (219.2*F) coolant temp. FYI