A couple weekends ago, I started experiencing a problem concerning my car (2002 Honda Civic EX) - which I've been told isn't really a problem. (?!)

After startup, the car would suddenly - with my foot on the gas - decelerate. It was seem like it's stalling, but would then go back to normal after a few seconds. Another minute would pass with this problem continuing throughout. Finally, the problem would stop and the car would be fine......and the problem would not occur again until I shut the car off and start it up. And even then, it would not occur every time I started up, but maybe a few startups later. So it's mainly a startup problem, as the car is OK after I've driven it about a mile.

Also, I've noticed in the last several days the car now shakes after startup (sometimes while I have the car still in park) and I've needed to shut the car off to make that problem go away (but it would still "stall" and decelerate for that minute or so of driving).

I've taken it to 3 mechanics - one of whom was able to hook a computer up to the car - and after checking the car and the systems they've all said (a) they don't know what's wrong (2 of them were able to experience the problem upon start up), (b) they've never seen a Honda do this before, and (c) it's actually not a serious problem.

My "check engine" light came on once, and that was because - for a time - I was pressing down on the gas hard whenever the deceleration would start and the car would resume acceleration; I brought it to a mechanic (the one with the computer) soon after.

What kind of thing would cause this? I've heard lots of explanations - loose sparkplug, fuel injector, transmission - but I keep experience the problem and keep thinking, if it goes on for much longer, it *will* be a serious problem sometime down the road.

Thanks for whatever help you can provide. Hopefully I'll have a list of things the next time I go into the shop...
Sean