Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
can you tell me the make of the cold air intake and what parts of the stock intake it replaces?
does it change the position of the MAF sensor in any way?
looking at this intake online it appears to re-locate the MAF sensor in a new socket?
so I'd check that the new location is the same as the OEM one and the new socket isn't somehow blanking the end of the meter off or masking it somehow
OK if you can hear air escaping / hissing then this could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.
Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.
The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane or brake cleaner around each joint in turn. If the engine rev's up you've found your leak. Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident. Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.