Is there a sure way to tell that I have a vacuum leak?? heres my problem. On my first 2 starts when the engine is cold it will start, go to 1300 rpm and in about 5 sec. drop till it dies unless i give it gas. That is only for the first 2 times. when it is cold it doesnt idle correct, it is a little high and fluctuates a little. When it is warm, it idles at 750 in park and about 700 in gear, a little high but decent. I am pretty sure that I have a vacuum leak that the computer is compensating for. Is there a way to tell besides spraying starting fluid all over the engine?

 

dont spray all over engine, just short bursts at egr and all vacumn lines and fittings, you dont want to confuse where it was picked up at also let air clear out between checks

 

They have what is called a smoke test for vacum leaks. if you can find someone with a machine that is the best way to tell. You hook the machine up to a vacum line from the engine (the vacum for the brake booster) and you put plastic over the throttle body (the intake portion) and let the machine go to work. If you have a vacum leak you will see it.

 

just an update, I asked my fathers friend who is a mechanic and he said that they have a mechinacs stethoscope to find things such as vacuum leaks, and exhaust leaks, they also have an 8 inch probe that you can pinpoint if the fuel injector is working or in valves are sticking, I fixed my hesitation problem with it, it was the best $15 i have ever spent at sears, it is craftsman part no.945164 if anyone is interested.

 

I have one of those stethoscopes but haven't really found a way to use it except for putting it on the injectors to see if they are pulsing. How did you fix your hesitation problem with it? How do you detect a vacuum leak with it?

 

Instead of putting on that 8in. metal probe, take it off and listen, with it off you can hear sounds. It worked great for me.

 

My hesitation problem was the vacuum line underneath the TB, from the driver side get to TB level and look under it. There should be a vacuum line and it only created a problem when I hit the gas not even at idle. put the stethoscope near that line and listen. Hope this helps.