90 Spider--problems continue

["Derek Kaznoski" <sweetpea1998@domain.elided>]

The saga continues...

I got the plenum chamber all lined up, but the car is still running poorly, 
i.e., rough idle (worse after 30-60 seconds), hesitation/stalling with 
takeoff, missing during even mild acceleration ( not severely, but 
noticeable), improves when backing off throttle, difficult to start after 
stalling but starts OK after it sits for a few minutes.

The problem is obviously deeper than the intake (I haven't been able to 
isolate an air leak, but I haven't used propane or WD-40.  I do know that 
all the individual pieces have no tears or cracks and seem airtight).

What if the basic timing is off?  Can this cause my symptoms?  What would 
throw the timing off?  Can backfiring/severe missing throw the timing off? 
(Previously during troubleshooting I accidentally started the car a few 
times with an injector connector unplugged.  I know, I'm a bonehead) Could I 
have damaged something deeper (shudder)?

Another thought:  could this be a fuel pump problem?  I haven't been able to 
check the fuel pressure because I can't find a tester to fit my car around 
here or on the 'net. (I did replace the fuel filter).

Some background that may help: First, the car has 62K miles and you could 
eat off the engine.  There are no leaks anywhere (even the backside of the 
engine).  The previous owner maintained it perfectly.  My local garage said 
it was the cleanest Spider they had seen since they were new. The point is, 
this is not a car that has been abused and neglected.
We had to evacuate during hurricane Floyd (I wasn't about to leave it 
behind!).  This entailed about 10 hours of sitting in 0-10 mph traffic, 
mostly at idle (OK, so now it's been abused a little).  The car did fine, 
only occasionally getting 1 to 2 ticks above the 175 degree mark.  No idle 
problems or missing. The next day, we drove at highway speeds about another 
3 hours, and the following day drove 5 hours home.  The car ran perfectly (I 
remember thinking it was almost scary how well it was running.  I guess I 
was right).  I'm not sure what toll this trip may have taken on the car.  
The problems started during the following week.  Please see the diy_efi list 
for the rest of the story ("Motronic 4.1 newbie").

I'm reaching the end of my VERY limited expertise (though I admit the 
learning process has been fun).  I'm not sure I ready to tackle the timing, 
because I will likley screw something up.

Any final suggestions before it goes to the shop?

Thanks,

Derek Kaznoski
'90 Spider Veloce
http://earthlink.home.net/~derekshana/alfaright.htm

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