So I took my car on a longer drive this weekend than it is used to. 4.5 hours straight each way. Some time during the drive back, the idle decided that it no long enjoyed being at 800 and jumped itself up to around 1200 where it is a little more bouncy. Does anyone know what could be causing this. I searched, but couldn't find any threads relating to this issue. The car is an '80 with a stock motor, carb, exhaust, etc. Any help or suggestions would be greatly appreciated. Thanks in advance.
-John

 

bump

 

It sounds like you developed a vacuum leak along the way. Time to start digging around. with a 400 rpm jump, I'd imagine it's gonne be a decent sized leak.
Good luck
Brian

 

hmmm.. hadn't thought of that, I will check it out. Thanks.

 

Any ideas as to where this vacuum leak might be. I went to look and realized I have absolutely no idea what I am looking for. Any guesses would be of help. Thanks.
-John

 

spray carb cleaner around any vac lines, base of carb and manifold to block. Just a little bit mind you, it wont take much for the engine to respond to it. When it engine RPM jumps you have found your leak.