'Curly Q. Links' wrote:
> Jez wrote:
>
>>Thanks Curly. I've had a look around on google groups and other people
>>have posted similar problems related to the TPS. I'll try the multimeter
>>test when I get a spare mo.
>>
>>The car doesn't have a cruise control (unfortunately!). I do about 50%
>>highway driving however the previous owner may have had a different profile.
>>
>>One question still lingers - why would the RPM vary though? The speed
>>(as far as I can remember) stays more or less constant. This is why I
>>was originally concerned about the transmission.
>>
>>Jez
>
>
>
> ============================
>
> The quicker way to see if it's the TPS (and this works WAY better with
> manual transmission). Put the car in first gear, and drive at the exact
> RPM where you have trouble. This might be jogging speed in first gear.
> If it's got a TPS problem, you might just see / feel it more clearly in
> first gear. My Ford Aerostar rod like a bucking bronco when the TPS went
> bad (manual tranny).
>
> O.T. Have you ever used injector cleaner? You should, maybe a couple
> times per year.
>
> 'Curly'


I checked the TPS today and it seems fine. There are no abnormal
variations in resistance. I put some STP injector cleaner into the tank
at the last fill. Time will tell if that solves the problem! Thanks
again Curly.

 

jim beam wrote:
> Jez wrote:
>
>> 'Curly Q. Links' wrote:
>>
>>> Jez wrote:
>>>
>>>> Hello,
>>>>
>>>> I have a 1996 Civic with 77,000 miles and automatic transmission.
>>>> Generally, it's in very good condition although lately i've noticed a
>>>> very specific condition which is my cause for concern.
>>>>
>>>> The specific condition is when the car is at roughly 35mph, 3rd gear
>>>> with light engine load (i.e. a gentle hill) which demands a specific
>>>> throttle setting to hold speed. This causes the engine RPM to oscillate
>>>> between 1900 and 2100 with a period of 1 second. I can both hear the
>>>> note of the engine changing and see it happening on the gauge. Simply
>>>> changing the accelerator position stops the problem.
>>>>
>>>> Is the transmission starting to slip? Is this the start of a big
>>>> problem or just a little niggle? I tried replacing the transmission
>>>> fluid recently with Dexron III (it was due for a change). Gear changes
>>>> are slightly smoother but it didn't fix this issue.
>>>>
>>>> Any comments would be much appreciated! Thanks,
>>>> Jez
>>>
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> The problem with the RPM sounds just like a TPS problem, but it's
>>> unusual for your vehicle to have it at such a low mileage. Do you live
>>> on flat land and use the Cruise control all the time?
>>>
>>> Get hold of a multimeter with a needle (not digital) and unplug the TPS
>>> (back side of the throttle) and set the Ohms scale to 10x or 100x, hook
>>> up to any two of the TPS pins, and if the meter swings when you open the
>>> throttle, you've got the common and one of the other two. SLOWLY open
>>> the throttle and watch the needle. If it spikes offscale at the same
>>> position as 1900-2100 rpm, you've found that your TPS is shot. Good luck
>>> on an inexpensive fix. I used to have an e-mail address for a russian
>>> guy who could get you one on the BLACK MARKET :-(
>>> Use Google groups to search for tps. Some have found sources for the
>>> potentiometer (only). It's really just a pot, like the one in your
>>> volume control on your stereo.
>>>
>>> 'Curly'
>>
>>
>>
>> Thanks Curly. I've had a look around on google groups and other people
>> have posted similar problems related to the TPS. I'll try the
>> multimeter test when I get a spare mo.
>>
>> The car doesn't have a cruise control (unfortunately!). I do about 50%
>> highway driving however the previous owner may have had a different
>> profile.
>>
>> One question still lingers - why would the RPM vary though? The speed
>> (as far as I can remember) stays more or less constant. This is why I
>> was originally concerned about the transmission.
>>
>> Jez
>
>
> so, what code are you getting from the scanner? if there's a fault, it
> /will/ be detected & stored!
>

There are no codes reported. I've also checked my haynes manual and
there are no codes related to transmission slipping. How do I check
which transmission I have? The haynes manual lists:

S1LA - 4-speed auto with lock-up clutch
S4PA, S5MA - 4-speed auto with electronic control
S4XA - 4-speed auto with Transmission Control Module
AR4A - 4-speed auto controlled by Powertrain Control Module (PCM)

I'm suspecting it's only got the basic electronic one but not sure.

What else could be causing this? I've tried injector cleaner and I've
checked the TPS as described by Curly.

I appreciate this is a fairly specific problem which may be caused by
any number of things!