make shift vacuum test

[dub-disaster]

trying to sort a porblem i have with kangarooing on the transition between on and off throttle only happens in lower gears (3 or below) usualy when down shifting coming onto a round about etc..etc.. can also happen on the transition between on and off throttle especialy in 2nd gear.

I thought the fact in only happens in lower gears would mean its suspension related but i have checked all over subfram and everything is tight only thing with any movment in it is the powerflex bushes any one had this problem before? i may replace with nylon but i want to check for air leaks first

My main question is, is it possible to check for vacuum leaks by blocking of both ends of the T-piece on the throttle body with nylon bungs attaching a pressure guage and a hand pump into one of these nylon bungs then with the throttle plate open pumping up the pressure watching for pressure drop and listenining for leaks/ soapy water trick ?? just wondering if the pison rings will seal against the block well enough not to leak any pressure by them when cold or if there where any other parts of the intake system i might have to blank off ??

 What do you think ?

[cheys03]

On a GT injection setup I checked for vacuum leaks by removing the intake tubing from the throttlebody, running the engine, then placing my hand over the TB until the engine stalled. I kept my hand there for 5 mins and still there was a good vacuum so deemed it to be ok. However, I was pretty stupid - don't use your hand!! Use a piece or rubber or foam which will hold the seal and not disintegrate under force. It left a nice mark on my hand for an hour or so :/