most vacuum leaks are in hoses that are disconnected or have holes in them you can also take a bottle of water and spray it along the side of the intake and base of the carborater if the motor bogs or you here it suck the water in you have found you leak but it can be a leak under the intake and that is a bigger problem to find buy a can of starting fluid and spray it near the gasket and vacuum hoses and if the engine increases its rpm that is where the leak is
The year, make, model and engine info would help but a serious vacuum leak could do that.
1) normal operation when cold or 2) vacuum leak cause by shrunken gasket
A bad IAC (idle air control)or vacuum leak. Check for bad vacuum hoses first, the IAC is around $50
vacuum leak or fuel pump Randy
The year, make and model info would be helpful but a large vacuum leak could do that.
usually there is a fuel leak internally however it can also be an air leak
The racing up and down at idle is call enging loping, usually caused by a vacuum leak. It could also be caused by a sticking choke at the carb. Whatever the case may be, you will need to start by hooking up a smoke machine to find the source of the leak. Also check your coolant level. my 1991 Toyota 4x4 22re had the same race up and down idle. it was a low coolant level.
vacuum leak. my 95 Monte Carlo did it. once in a while it would race to 2500 rpm then settle down like normal. not easy to find , but a cheap fix.
Actually, there might be some kind of vacuum leak or bad vacuum connection somewhere. When you step on the brake, the power brake booster under the hood draws vacuum from the engine ... so it could be related to that. Check all your vacuum hoses and connectors for leaks, cracks or loose fittings. A quick and dirty fix for hoses with small cracks is to wrap some electrical tape around the cracked area. Such fixes are NOT RECOMMENDED BY EXPERTS, of course, but if they work for a day or two, they're likely to work for years.
That is normally caused by an air leak in the induction system.
90% of the time it is a vacum leak check all ur hoses goin to the intake also check the idle air control valve on the back of the intake
A five letter word for a race car engine is a motor.