Without ever throwing a code or a stored code, and very intermittently- sometimes after driving in stop and go traffic, but also sometimes within just a few blocks of driving- the car will ‘lurch’ forward as it is coming to a complete stop. It never lurches in higher gears. Sometimes the lurching is just noticeable but not severe, but a couple of times it has been extreme. Usually when this happens, if I continue to drive it, the RPM’s at rest go above the normal .75 and the car will maintain the cruising speed achieved without depression of the accelerator. 2 or 3 times after this has occurred, when putting the car into park, the RPM’s shoot up to between 2 and 3. Twice, after shutting off car and restarting with these symptoms, the RPM’s rise right back to same levels. If left undriven for a couple of hours, the car goes back to driving just fine.

Things done recently (some general maintenance, some attempts to resolve the issue):

· Timing belt, water pump replaced

· New engine mounts

· New Intake Air Control Valve

· New rear brakes pads/rotors

· Transmission fluid service

· Coolant and oil change

· Power steering o ring replaced

· Factory Idle reset (DIY) but followed service manual troubleshooting instructions

· Car examined for vacuum leaks, none found

· All fluids holding – no leaks

The year and make for this car does have some pretty significant transmission issues, but the mechanic/friend who did most of the work does not point to a failing transmission as cause. The car shifts gears well up and down, doesn’t ‘lock’ in a gear during highway driving and during these episodes there is never an odor.

Other items to consider:

· Throttle position sensor

o I have seen some vids on using a Dremel to cut factory screws so you can loosen and alter settings

o Can it be ‘tested’ to determine if failing?

· Throttle body cleaning

· Throttle cable – too tight? Can intake get dirty?

· O2 Sensor – again, can it be tested – if no code thrown seems unlikely

· Dirty EGR Passages- clean?

· Air Mass Flow Sensor – clean MAF?

· What is torque converter, and does it lock up?

· Faulty A/T clutch pressure control solenoid A/B assembly

Been in 2 different shops one independent and one Honda dealer shop and both haven’t been able to replicate while there so don’t dig very deep. It would seem (and the mechanic who has done previous work is willing to noodle with me on this) the next area to explore is the throttle stuff, probably the TPS sensor, to see if it is set to specs and if not, to reset it, clean the body/intake, check the cable and see is that changes things??

 

Just some thoughts; maybe you've already ruled out some of this stuff.

Lurching when stopping sounds to me like the transmission is making a rough downshift. That suggests the idle RPM is too high. Did you go through the procedure of setting the base-idle with the IACV unplugged? The idle-control system doesn't get along very well with "personalized" adjustment.

The throttle-position sensor can be tested. Back-probe its electrical plug and one of the wires is supposed to sweep up & down smoothly. I don't remember the wire colors or the correct voltage when the throttle is closed. Search in General Tech and here in Engine/Internal for TPS checking. Not only the voltage at idle, but if you smoothly open & close the throttle the TPS signal should be smooth, not jumpy.

The throttle body CAN get dirty and mess this up. You would have had the TB off when installing the IACV, so you probably know if it's clean.

The throttle cable. It's important that the cable goes slack when your foot is off the accelerator pedal. NEVER use the cable to set the idle speed. The throttle plate itself should close completely. There's a little stop-screw similar to the idle-adjust on an old-school carburetor. NEVER use that to adjust anything - it's ONLY supposed to just barely keep the throttle plate from wedging stuck closed. Unhook the throttle cable and move it in & out to see whether it's gummy or excessive friction. It should slide nicely.

Your PCM is pretty good at identifying a bad O2 sensor, so I don't think it needs to be tested. It would throw a check-engine-light. That would be different if we were talking about a 1996 car. I think it's the same story for the EGR passages.

I don't think your car has a MAF. Not until 2005-ish.

Torque converter is kinda like part of the transmission. It's what allows the transmission to slip when coming to a complete stop in D or R. If it would lock-up at that time, it would be worse than lurching...

AT solenoids have trouble codes, so they would probably throw a CEL and/or a flashing "D" lamp for transmission trouble codes.

Bottom line... From your descriptions, I suspect the idle-speed stuff.