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				Find the leak
			 
			
			What is the best way to find a vacuum leak? Upon returning from a two week vacation I started up the  porsche and for the first 10 to 20 seconds it had a good idle and then all of a sudden it would miss and backfire. I had to feather the throttle to keep it running. 
		
	
		
	
			
				After warm up it still ran rough. checked the vacuum and guage read about 10 inch hg. Shouldn't it be a bit higher? Is it wise to spray carb cleaner around areas to find leak? It's a 1983 SC Thanks for any help bk  | 
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			 Slumlord 
			
			
		
			
				
			
			
			Join Date: May 2001 
				Location: Canada 
				
				
					Posts: 4,983
				 
                
				
				
				
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			Use either quick-start (spray it on the hoses) or an unlit propane (or acetylene) torch. As the gas is sucked into the engine your rpm will rise.
		 
		
	
		
	
			
			
		
		
		
		
		
			
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	84 Cab - sold! 89 Cab - not quite done 90C4 - winter beater  | 
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			Thanks the torch seams like the way to go 
		
	
		
	
			
			
				
					bk  | 
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