those flashes sound like a MIL code 34
i found this in one of my training books, maybe it will help :o)

Fault Code 34 - MAP Sensor Circuit, Signal Voltage Low (High Vacuum)
TEST DESCRIPTION
The numbers below are a reference to the bold numbers in Figure 37.
1. A Code 34 is indicated during the following conditions:
a. The engine speed is less than 600 rpm and the manifold pressure is indicating less than 13 kPa (20 inHg) (vacuum gauge) for one second or more.
OR
b. The engine speed is greater than 600 rpm, the throttle angle is greater than 15%, and the manifold pressure is indicating less than 13 kPa (20 inHg) (vacuum gauge) for one second.
2. This test determines if the MAP sensor has a fault or the ECM or wires have a fault.
3. This test causes a high signal voltage to check for an open-circuit in CKT 427. If the Test Light illuminates brightly during this test, CKT 427 is indicating a short circuit to ground. If the SCAN TOOL indicates greater than 4.0 volts during this test, CKT 637 can be checked for 5.0 volts (correct) at terminal C.
OTHER TROUBLESHOOTING CHECKS
A poor connection in CKT 416 will cause a Code 34.
The table in the troubleshooting chart can be used to check the output of the MAP sensor at an indicated pressure.
If the engine operation is not constant or not regular and a Code is indicated, disconnect the MAP sensor. The electronic control system goes into the backup mode. If the engine operation still is not constant or not regular and if additional codes are not stored, do the Troubleshooting, Poor Operation.

a faulty MAP sensor can cause the motor to run badly and can cause it to not run at all, it may have been giving you trouble all along, either the sensor is bad or a bad connection to it.

This info was a snippit of a broader set of instructions to troubleshoot poor running conditions.