Car hiccup

i own a '99 honda accord LX (automatic) with about 103k miles on it. every day in the morning when i first drive my car down the driveway and onto the street i experience something when I put the car in drive - when i shift from reverse to drive (while my foot’s on the brake) I almost immediately feel (what i can best describe as) a hiccup in the car. It feels very much like it would if the car was a stick-shift and the jump just before it stalls. this one is not as apparent, but still quite noticeable. Even if i don’t keep my foot on the brake and i let the gear of drive take over i still feel the hiccup as well as a delay in the acceleration. And on top of this there inevitably another 2 hiccups once i stop and start at the 2 stops signs within 1/8 of mile from my house. I took the car to oretty trustworthy auto shop that specializes in transmission and they held the car over night, but for some reason they didn’t experience it when they drove it or see anything questionable about the transmission when they looked it over. my suspicion is that they let the car sit for a few minutes before they drove it - this seems to always keep the hiccup from occurring. i’ve been told that it’s probably a problem with my transmission but i hope the auto shop guys said they didn’t see anything and also because it’s a fix that can be pretty expensive. please help and advise. - thank you, keith

This problem is more likely a driveability problem with the engine. What you are probably seeing is a backfire into the intake manifold followed by a stumble i.e. lack of power. Both are symptoms of a lean condition on warm up. There might be a vacuum leak somewhere that is letting unmetered air into the intake system. Alternately, there might be a fuel delivery problem that keeps the injectors from delivering the correct amount of fuel for the air being metered. Also it could be a slightly out of tolerance sensor that is telling the computer that the engine is warmer than it really is. Have an engine tech do some diagnosis. Hopefully they will be able to narrow the driveability problem down to a specific cause.

Let us know what happens.