1994 Integra: Strange RPM Behavior (Part 2)

I've had this problem for about a year now. In fact, I had a thread
about it at one point here:
http://groups.google.com/group/alt.autos.honda/browse_frm/thread/da3b28dad786d5db/37db382debfb1365?lnk=gst&q=1994+acura+integra+ls+rpm+behavior#37db382debfb1365

I have about 185k on the car now. Since that time I've had the
transmission fluid changed. My mechanic seems to think it may have
something to do with the torque converter. The problem is about the
same and doesn't seem to be any better or worse, just somewhate
annoying. Here is the original message I posted last year (see the
link above for the original replies):

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I have a 1994 Acura Integra LS automatic with about 175k miles. I've
noticed that something occurs when I'm cruising in the higher speeds.
When I'm going about 70mph the RPMs are roughly 3000. When I hit the
gas to speed up to 75 or so, the RPMs sometimes (not always)
*decrease* by around 200 RPMs . Then it will jump back up to the
correct higher RPM a few seconds later, especially if I release the
gas slightly. Please note that I'm not hitting the gas hard enough for
the transmission to gear down when this happens. At first I thought
that it was just the RPM gauge behaving strangely. But, after doing
this a number of times, I can actually feel the engine losing the PMs
ever so slightly. I can't seem to recreate this issue in lower speeds,
however.

Any ideas what could be causing this and how to possibly fix it?

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it's mechanically impossible for the revs to drop while the speed
increases - unless the lockup clutch is disengaged, you're going down a
hill and you take your foot off the gas. if the revs drop when you
increase gas, you likely have a "flat spot" caused by something like bad
ignition or blocked egr, but that would be accompanied by a decrease in
speed also.

 

Hi,
How old is the fuel filter? EGR, ignition parts(wires, plugs)?

 

The fuel filter might be just a couple of years old and the other
parts are in pretty good shape I think. I would imagine if it was any
of those parts the car would run badly no matter what the speed,
though. My problem only occurs at higher speeds. Otherwise, the car
runs great. Thanks...

 

did you check the items i listed - or does "otherwise it runs great"
mean you don't have to do that? i mean, usenet means you stay inside
where it's warm, but it doesn't fix your car.

 

The engines rpm drops by about 200 - 300 rpm when the torque converter
lockup engages (load on the engine increases) and jumps up when the TC
lockup disengages (trans operates in limited slipping mode)

i've had no experience with Acuras, but in Hondas, the lockup should
occurs at about 50-55 mph on moderate throttle and should only
disengage when you hit the brakes, or go up a steep hill, or get off
the gas pedal (takes a moment), or pound hard on the gas pedal
(immediately)

If the TC lockup engages and disengages at the slightest change of
throttle or the vehicle's speed, or for no apparent reason at all when
cruising, then incorrect throttle valve cable (aka kick down cable)
adjustment is most likely the culprit. i'm thinking your cable is
loose (too much free play), if it is, tighten it up!! Dont continue to
drive your car in this condition or the TC will fail!!!!

i've learned that in newer AT, the lockup mechanism works at lower
gears too, but i'm sure none of 1994 vehicles has it, that's why you
dont see sudden drops and jumps on the tach at slower speed

oh and make sure the fluid is not burnt and filled at the correct
level

 

jim beam-
I'll be sure to bring those items up you mentioned with my mechanic
when I bring it in. I appreciate you taking the time to look into this
for me.

 

I will definitely have my mechanic look at the throttle valve cable,
too. Thanks for your help. I appreciate it.