Glad to see that the poor fuel economy has been fixed. I'm not sure where you should go next on the hesitation issue.

On an unrelated note, have you flushed the coolant system? It's a cheap maintenence option that I strongly recommend. (I just changed out the coolant in my sister's Civic. It was practically mud after so long.)

 

Any CEL codes?

Did you adjust the ignition timing after the plugs, wires, cap, and rotor were replaced? Was the ignition timing adjusted with the engine idling to spec and the service connector jumped? If the answer to all of these questions is yes, then I would recommend that you try a Seafoam treatment of the gas tank and intake manifold (see forum DIY section).

 

Here is that seafoam DIY by the way: https://www.hondacivicforum.com/foru...ad.php?t=14612

 

The CEL is not lit up, and has not come back since the timing was adjusted. I got the ignition timing adjusted by a mechanic because I didn't have access to a timing gun. He did the procedure as per the service manual, so I assume that he did it with the connector jumped and the engine idling. This was done after I had already changed the plugs, wires, cap, and rotor. I was still getting 22mpg after I installed the new ignition components were installed, and I drove like that for about 3 weeks before I got the ignition timing adjusted. I put through 2 more tanks of gas...one yesterday and one today doing a full day of driving each for work, and I averaged 29.7mpg on the highway. I tried revving the engine while in park, and I get no hesitation if the car is in park, or when I am coasting in neutral. This morning I started driving and it was giving a hesitation while in drive (stuck at 2k rpm, then all of a sudden springs to life and hops up to 3k rpm), I then put it in neutral and it revved fine with no hesitation, then I dropped it back in gear and got the same hesitation again. It only does this when it is in gear. Now that might be just because the motor is under load, or it could be the tranny. Could this be related to the linear solenoid issue with the automatic transmissions? TSB# 00-012. Like I said above, once everything is warmed up, this does not happen at all. I will probably try the seafoam either way. I have heard good stuff from guys using it on their Titans, and I would like to use my civic as a guinnea pig before I dump it into my truck as well Thanks again for the suggestions.

 

Does the problem start just as the engine is beginning to warm up (is near or has just reached normal operating temp)? Or when the engine is stone cold?

 

It is most severe when the engine is cold, but it will also happen if I warm up the car first by idling. It occurs within the first minute of actually having it in gear and driving, regardless of whether I warmed up or not, but certainly more frequent if I don't warm the car up. If I stop the car and leave it for 10 min or so, the coolant temp still registers on the guage so not stone cold but the hesitation usually still happens for the first minute of driving, always at 2k rpm. If I stop for less than 5 minutes it won't hesitate upon starting back up. It's like the first couple times it gets to 2k when I start driving it gets stuck there and doesn't respond to the throttle for a few seconds, then springs back to life. After it does it once or twice, you are good. This morning it did it when I first started the car, I drove all day for work stopping for 5 minutes here and there and it didn't happen once. I then parked it for an hour after work at a friends house. When I left it did a pretty long hesitation at 2k rpm as I pulled out of their driveway. After it warms up it drives perfectly. Not sure if it's tranny related or not. Any advice would be greatly appreciated! Thanks.

 

Do you still have CEL code 45 or any other CEL codes?

In addition to doing a Seafoam treatment, also try unplugging the connector to the primary O2 sensor to see if the problem goes away.

If you still have the problem, measure the fuel pressure with and without the vacuum hose to the fuel pressure regulator (FPR) disconnected. This will reveal whether the FPR is malfunctioning.