2003hondacrv

Hi
Took my car in last week (Mon) and had the thermostat replaced and a new gas cap. Told them car was sputtering.
Beginning on Fri I noticed my gas pedal wouldn't initially depress. I thought maybe something was stuck down there but no.... it eventually depressed and since then I've only driven the car once Don't trust it.

Just turned car on now (SUN) and it initially didn't turnover and after a few tries it started but w/lots of sputtering and there's a mapley (sp?)/exhaust smell. The check engine light came on a few days ago but figured that was b/c the gas cap was recently replaced & would eventually go away.

It's an '03 w/137K miles on it. Will take it back this week but wanted to see if anyone knew what the problem could be. Thank you!