Code 43 - Newbie - need help!

[bane01]

Hello all. I need some help. I just aquired a 1990 Honda Prelude Si from a guy who is moving out of state for grad school. The car was his brother's (who is in the Navy in San Fransico). They had nowhere to keep the car when the guy left the state. I bought it for a good price. However here is the deal as I now know it, hopefully these facts can help diagnose the potential problem.

 

VIN # matches for 2.0 L engine.

Block says it is a B21A1, which is a 2.1 L from my research.

Odometer shows 226K miles.

Car was rebuilt (or had engine replaced) in ~ 2000 by someone getting their Honda Certification.

Car has aftermarket intake installed.

I estimate this engine/rebuild has ~ 100K on it (just a guess).

Car has only been cranked and driven around the block every couple of weeks for the last year or so.

Car has a full tank of gas that is probably a year or more old.

While driving the car home (~35 mile trip) the Check Engine Light came on about 15 miles into the trip.

Car did not exhibit any problems with power - ran smoothly and responded well.

Only saw tiny amounts of gray smoke on take-off a few times, not unexpected for car with this history.

Stopped at Advance Auto and asked if they could diagnose, not realizing they can only check OBD2, this is OBD1.

Suggested injector cleaner/fuel stabilizer based upon brief background info on car.

Added injector cleaner/stabilizer to tank.

Drove home remainder of trip.

Car still shows no signs of problems.

Researched on net and found out how/where to read code.

Code displayed is 43 - indicates "Fuel Supply System"

 

Okay, long story to get to the real questions.

Is it possible that the old fuel is causing this?

Would the ECU have been changed or is that necessary if the guy who swapped the engines did change from factory 2.0 to 2.1? If the ECU should have been changed, but wasn't, should we expect the CEL to come on?

I know that there are a lot of sensors that could require changing (MAP, O2, etc. and possibly the fuel filter as well), my main question is, as long as the car is running fine and no emmisions testing is required, is there a problem or danger in driving the car?

We are thinking of resetting the ECU and seeing if it comes on again. At this point, I am not excessively worried until we run out the old gas and put a clean tank through it but would really appreciate any helpful suggestions.