I'm currently on a road trip. 500km in on a highway with no services, my 93 Civic Si Hatchback sputters and dies. Catch a lift remaining 50km in to town to pick up some parts that might fix what I think is the problem, but come back to a car that drives fine. Elapsed time: 1.5hrs. Added fuel + fuel conditioner for good measure. Drove remaining 1000km to my destination without incident. Needless to say, I had a lot of time to think about what might have been the issue, but I would like to get some unbiased opinions.

Symptoms/status:
- Cruising along in 5th gear when I hear the engine start to struggle, pressing the gas pedal seems to do nothing
- Am able to limp along in 2nd gear for a bit, finally this dies off too
- Once stopped, am able to turn the car over, idles fine seemingly
- As soon as I put it in gear and released the clutch, the engine struggled and there was no power to the transmission
- No CELs (except for a known one for the O2 sensor that only appears at low RPM when in high gear)
- Had 1/8th tank of gas left
- Was slightly low on coolant but engine temp was steady at 1/4 up the indicator (normal).
- Oil level normal.

Weather:
- Very hot (+33C / 91F), sunny, dry - but A/C was off at the time
- When I return 1.5hr later (around 9.30pm), weather is noticeably cooler - likely ~22C / 72F

Following parts are new / nearly new:
- Plugs, wires, rotor, fuel filter - using HQ or OEM parts
- IACV recently cleaned

My thoughts: bad gas, bad igniter coil in dizzy, bad fuel pump, bad main relay

Would appreciate your input.

 

1/8 tank o gas? My ef gets cranky when the gas gets low and does what you just described.

 

Car has always driven fine even with fuel level nearly on Empty, in the red zone. Also, car seemed to drive fine again after 1.5hrs, but still with 1/8 tank.

 

From your description of symptoms, it sounds like the fuel pump is giving out. I had the exact ailments as you described re: my del sol. I took a gamble, replaced the fuel pump. And problems went away. Runs like a top again.

 

Catalytic converter might be plugged.

 

Update: Since I was on the road, and had a replacement O2 sensor with me, I had a shop swap it in. Still had occasional stalling out issues, though. Finally, I got a code 43, which is the dreaded "fuel supply" problem; car stalled and did not want to go at all. Thankfully, wasn't far from the town I was visiting and it needed a tow. Got it back and car drives fine again ... gah, intermittent problems are notoriously difficult to pinpoint. But, Service Manual says at this point to check FPR, filter, pump. Filter is nearly new. Picked up a used FPR and pump .... after swapping in the pump, no more check engine light. Did everything I could to bring it back, but no go - it stayed off. So, problem solved! Thanks to 'arizona del sol' for also pointing me in the right direction.