A not working heat blowing all the time

Airbag light stays on! Was told it is the sensor in the seats that needs to be replaced. I want to have that reconfirmed before having repaired. Need a reliable, dependable, affordable shop recommended.

Replace crankshaft position sensor cleared code drove 400miles ,egr,evap&o2sensor not ready to pass emissions

The heater did not work this winter and now the heater is stuck open.The av works but the heat over powers it

Car started missing 3 years ago after filling up one night. Next day started missing and it pops up knock sensor and random misfire on scan tool.i cleared the codes and ces light comes on about 5 mins later. I replaced spark plugs a year ago and still has miss. Driving down the interstate it drives fine at high speed but misses more in town and jerks. Will replacing the coils, new plugs and reset knock sensor fix the miss?

how much to repair a leaking transmission

It doesn't do it all the time

I checked all the bulbs, they are fine. As well as the fuses.

I just had to change blower motor speed control had no air flow at all

the light stays on even tho it seems to be running smooth
1998 infiniti i30

and stays on but the car seems to be running ok.
1998 infinity i30

Check engine light is on (sometimes flashes). I just replaced a damaged fuel injector- gas was coming out of tailpipe. When I replaced spark plugs some time ago, was told there was oil in the sockets. Was also told that it could be head gasket. What are the symptoms for that and approx. cost for repairs? Would I have to replace all engine gaskets?