Timothy Yhtomit

Hello im running a stock b20 with skunk2 intake manifold and plm 2.5 headers in my 91 civic hatchback. A few years ago the car was all obd0 with the b20 and it ran fine but the car sat for a few years till recently I brought it back but as obd1 with obd0 injectors and ever since I brought it back it has been running rich and when you shift you can hear it backfire from the exhaust but other than that it runs fine, it idles fine, no CEL, drove around town a few times and is smooth except the smell of it running rich. Went to the drag track today and when I launched I felt a loss of power. Another example is when it was all obd0 stock b20 no bolt ons, it ran 15.0 at the track but this time I went and I was consistantly running 16's. Anyone got any ideas on what it can be? Maybe o2 sensor?