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Hesitation during acceleration when cold on Accord V6

I have a 2003 Honda Accord V6 that has some acceleration hesitation and general jerkiness, usually noticeable when the car has been sitting for a long period of time (overnight). The symptoms seem to dissipate after 5 - 10 minutes of driving.

When I begin accelerating, the car feels like it hesitates when shifting from 1st to 2nd gear. If I let off the gas a bit, then the car jerks a bit.

I’m sure it’s not the transmission, because the dealer said the fluid and everything looks fine. Additionally, I have another Accord (2000) that does have a failing transmission and the symptoms on that one are very different from this 2003.

A couple of months ago, I was getting a CEL and had a friend of mine read the code with his OBD tool. It indicated that Bank 1 Sensor 1 was bad. I replaced it with a Denso. I think the problem got better at that point, but has “worsened” again over the past month or so.

Any clues what this might be? Things I can try? Ways to narrow down the issue?

Thanks in advance!

It might be a dirty throttle body, those can get balky and stiff when cold, and free up as the temp rises. But I expect more likely this is a mixture problem. The CEL code you had was reporting a type of mixture problem, and I expect you haven’t fixed it yet. Besides bringing all the routine engine maintenance up to date (on your car this is probably just the spark plugs & engine air filter) , and doing a general visual inspection for broken vacuum lines, probably the first thing I’d do is ask a shop to clean the mass airflow sensor.

Thanks for the tips. Going to get the spark plugs done on Monday and we’ll see what happens.

Is the mass airflow sensor easy to clean?

When you go get the spark plugs done, ask the shop tech how hard it is to do on your car. Usually it isn’t very time consuming, if you are lucky it is just spraying some cleaner from a spray can into the air intake port of the throttle body with the engine running. Auto parts stores usually sell the cleaner in the spray can so you just follow the instructions on the can. Of course this won’t work if your car doesn’t use an MAF. It won’t work on MAPs for example. I think a 2003 probably uses a MAF though. If you have a maintenance manual for your car it should say there.

Got spark plugs replaced and oil changed. Maybe it helped a little, but still seems to hesitate some. Car doesn’t have a MAF.

Other ideas?

Your shift problem is well known.

When was the last time the fuel filter was replaced?

When the engine is cold, the computer is in the open loop mode. This is where the demand for fuel to the engine is at it’s greatest. Once the engine warms up and the computer goes into the closed loop mode, the demand for fuel to the engine is reduced and the computer makes fuel trim adjustments from the signal from the O2 sensor(s).

If the fuel filter is restricted it can reduce the volume of gas getting to the engine when the engine is cold causing a hesitation when accelerating.

If you can’t remember the last time the fuel filter was replaced try that.

If the fuel filter was serviced recently, then you might consider having the fuel pump tested for both pressure and volume.