Either. Dispstick will roughen the idle. Cap will cause a stall... At 02:56 PM 12/2/1998 , Sachelle Babbar was inspired to say: > To test fo a vacuum leak, do I have to pull the dipstick or the cap? I > thought it was the dipstick. Cheers, Richard 88 90Q "Hannu" - K+N, new vac hoses, still 0.0 bar.... 88 Golf GTi - PRO Rally