# Catalytic converter **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [October 22, 2008, 3:19pm UTC](https://community.cartalk.com/t/catalytic-converter/21064 "2008-10-22T15:19:29Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![lillimack](https://avatars.discourse-cdn.com/v4/letter/l/b3f665/32.png) [@lillimack](https://community.cartalk.com/u/lillimack)\ **Post date:** [October 22, 2008, 3:19pm UTC](https://community.cartalk.com/t/catalytic-converter/21064/1 "2008-10-22T15:19:29Z")
'94 Mercedes S420/158K miles; engine runs great unless car sits unused for 5 days+. Then, sluggish initial acceleration, stalls(with rotten egg odor) until RPM hits 1500+. After 20-30 minutes, seems to clear up, then OK. Catalytic converter likely? ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [October 22, 2008, 3:27pm UTC](https://community.cartalk.com/t/catalytic-converter/21064/2 "2008-10-22T15:27:31Z")
It could be a lot of things, but the cat converter wouldn’t be on my list. My first guess is moisture in some part of the ignition system. I would replace the distributor cap, rotor button and plug wires if it has them. Maybe even the ignition coil. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [October 22, 2008, 7:47pm UTC](https://community.cartalk.com/t/catalytic-converter/21064/3 "2008-10-22T19:47:59Z")
I’m gonna guess that your fuel line is draining. The next time the car sits, try turning the key to “on” for four +/- seconds to pressurize the fuel line before turning it to “start”. Post back with the results.