I for unknown reasons got the car started after doing several diagnostics to find out why it would not start and now it putters (small backfire?) at idle - I did not notice anything while test driving. It had power and ran smoothly.

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HISTORY:
Freezing weather for two days before and while the car was parked after a 1.3 mile drive.

On starting the car it did not catch the first time (not really abnormal for the last several years). On second attempt with a little gas it started and was firing all over the place like the timing was askew. Tapping the gas did not help and when I stopped applying gas the engine stalled and would not start. It seemed to fire 'once' but not turn over and then it did not fire anymore.

1) Radiator water not frozen

12-09-08 and 12-10-08 \ temperature above freezing (59)

I went through the following checks:

2) battery – 12.48 V

3) fuel pumps – both operate by test from Relay

3) 25 Amp fuse in tact

4) distributor cap – some very slight black smudges along rim but no signs of arching. Electrodes show black eroded line at point of rotor contact – scraped loose material off with small screwdriver.

5) distributor rotor – looks good – outside contact edge is black. I buffed the edge and top contacts.

6) coil – primary 1.1 Ohm, secondary 11.17 Ohm

7) Air mass meter (AMM) – 2-3 (2.8 Ohm); 2-6 (362 ohm); 3-6 (365 Ohm)

*** NO START

8) Various out of sequence ignition wire tests.

*** NO START

9) Check for spark:
#1 – wet / firing
#2 – wet / firing
#3 – not wet (obvious vapor blowing out spark plug hole) / firing (not as big a spark as 1 and 2)
#4 – wet / firing (not as big a spark as 1 and 2 – like 3)
Engine made some puttering sounds during spark test.

*** STARTS \ rough \ tapping gas \ increase gas slightly \ stop applying gas \ engine running very rough \ a lot of exhaust \ run settles down with some tapping and time

Outside temp is 61 degrees, dew point 59 degrees.

Test drive and bring engine up to operating temperature. No hesitation, no loose of power.

Parked and idling there is a slight backfiring evident from the tail pipe. Exhaust plume is gone.

Stop engine and restart. (?)
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In January ’08 I replaced all spark plug wires, coil wire (Kingston), distributor cap and rotor (Bosch), and applied dielectric grease on the inside of the distributor cap and cable caps.

Other posts indicate possible problems with:

EGR valve stuck open?

Fuel Pressure Regulator diaphragm broken?

??????????

Are there other likely suspects that would cause a temporary "loose of timing" (starting failure) and puttering at idle?