I recently swaped a b18b1 into my 95 civic and once i started everything ran and sounded fine except for a bad fluctuating idele that surges between about 1000 to 3000 rpm. Any ideas that might be causing this? thnx

brady

 

vacuum leak

 

Yeap, had that problem too, but it went away after a few weeks... it's a typical swap problem, so I've been reading.

 

depending on how far into it you went, it could be a bad gasket on the intake manifold, or in my case it was a bad seal at the throttle body. Most times it goes away when it's warm since the metal expands and seals the gap. Also check your hoses and PCV valve...