I have a 2001 honda civic ex. I have had issues lately where my car sometimes acts like the throttle is sticking. ( when i first start my car it would idle fine but when i hit the gas it takes a few pumps before you hear the engine rev). Today it worked fine most of the day, the i went to a store, and when i came back out, my car was surging when I try to keep the gas at a steady level, and it also dies the sec i take my foot off the gas. I smell a strong gas/exhaust smell. Also my check engine light is on has been on for years (reads p0420, catalytic converter below threshold, I dont know if it can be causing current issue or not). Any ideas of what I should check?

 

Your catalytic converter can cause these issues. You may have a clogged cat., or possibly the reading from the primary O2 sensor is getting fouled by a leak (which could cause the fuel surging).

 

Pulled codes today, got p0336 crankshaft position sensor, p0300-304 miss fire all cylinders. And p0420 catalytic converter below threshold.

 

Sounds like you may have more going on then you thought.