Random hesitation
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Random hesitation
For several years now Ive been having this hesitation/ misfire issue with my car. on a completely cold start (morning or after like 4 hours) the car starts and drives fine. If you drive the car and let it sit for about an hour or so then go to drive again thats when I get the stumbling issue. The car will start fine but if you go to drive away it stumbles hard and seems to be misfiring. however if you blip the throttle over 2k or let the engine settle and warm back up it doesn't happen. its only on warmish restarts. Ive never gotten a CEL since this has been going on either, even while its (misfiring) stumbling. also if I let the car stumble the RPMS get verrrry low but the car will not stall out the ECU or IACV catches it. Ive been to several shops and replaced a lot of parts and still nothing has fixed it. ive learned to just live with it and I know how to get it to stop. Does anyone have any clue what could be wrong or is it just a gremlin that im going to have to deal with. the car runs perfect after its little issue on the restart or after I blip the throttle or clear its throat in other words. Ive also ran a code scanner while its been doing it and the fuel trim tables show that the car seems to be running lean when its misfiring leading me to believe that its a fuel delivery issue. The only fuel system part thats not been changed is the fuel rail and injectors. I haven't changed them as the resistance is in spec and Ive heard from lots of Honda experts telling me that Honda injectors almost never fail.
Parts replaced
Fuel pump
Throttle body with all sensors ( TPS, IACV)
MAP sensor
ETC sensor
Coils and plugs
crank and cam sensors
I also checked the resistance on the injectors and they all seemed to be in spec.
about a year before this happened I also changed the head gasket, WP, and tensioner.
Parts replaced
Fuel pump
Throttle body with all sensors ( TPS, IACV)
MAP sensor
ETC sensor
Coils and plugs
crank and cam sensors
I also checked the resistance on the injectors and they all seemed to be in spec.
about a year before this happened I also changed the head gasket, WP, and tensioner.
If you think a good mechanic is expensive, try hiring a bad one
Joined: Dec 2011
Posts: 32,017
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From: Midwest. Aiming about mid-chest
Rep Power: 518 
Re: Random hesitation
How many miles on the car?
VTEC engine or no?
Mileage, 150-180,000?
Unplug the front (primary, upper) O2 sensor.
Make sure you have an unlock code for the radio if necessary.
Disconnect the battery and leave a door open for like 10 minutes (to erase learned adaptive values from the PCM)
Reconnect the battery.
Drive the car through several cycles where you would expect it to act up. A few days if necessary.
The check engine light will be on because the sensor is unplugged, just ignore it for now.
If symptom is gone, replace the primary O2 sensor that you unplugged.
VTEC engine or no?
Mileage, 150-180,000?
Unplug the front (primary, upper) O2 sensor.
Make sure you have an unlock code for the radio if necessary.
Disconnect the battery and leave a door open for like 10 minutes (to erase learned adaptive values from the PCM)
Reconnect the battery.
Drive the car through several cycles where you would expect it to act up. A few days if necessary.
The check engine light will be on because the sensor is unplugged, just ignore it for now.
If symptom is gone, replace the primary O2 sensor that you unplugged.
