Ford focus zx4 05. Car starts but shut off. Engine light came on check codes and they are p106 and p171

go to any national chain parts store and they will pull the code for you-I'd guess based on what you wrote that it is a crank or cam sensor, or a bad ignition module.

If you smell fuel, it could be a glogged filter, it could be a bad fuel pump, it could be a bad ignition coil, it could be a bad catylatic converter. I would guess though by the info you gave, that the coil shorted out due to a faulty plug. Look under the car also for any sign of leaking fuel, your best bet at this point is to have a scanner hooked up to it to more closely pinpoint the problem instead of guessing and spending a lot of money on guessing

p0304-misfire no 4 cylinder--can be bad plug-coil -wire-problem with 02 sensor--fuel injector-bad exhaust valve-cat conv- poor ,compression -these are most of the reasons that an cause a misfire and yours is specifying the no 4 cylinder

code p 0306 is misfire detected no 6 cylinder causes electrics
more likely a bad injector , injector wiring or dirty tip

Please go to this page for engine misfire causes.

The P0106 code indicates a problem in the MAP sensor area. Did you reconnect the MAP sensor connector after the plug change or seat it properly?
The P0128 code has to do with the coolant temperature not coming up to operating temp fast enough, this usually means the thermostat is stuck open.

Have you isolated which cylinder it is? It may be a bad coil pack. You didn't say what the mileage of the vehicle is.

A flashing light is BAD. Its damaging the cat converter. I would check or replace the spark plug wires ( if all OK, then) replace the coil pack. I would not replace anything unless they test bad. but these car are known for bad coil packs.

Gas Filter? Then scan tool on it,to look for codes set when check light came on. Most likely a senor is old and out of range.

you will have to read the diagnostic code that the computer is sendig for the check engine light to activate