1992 Ford Tempo Shifting problems

I have a 1992 Ford Tempo GL automatic (4 Cyl/2.3L) that has started intermittently giving me problems when it tries to automatically shift between lower gears. I have to really press down on the accelerator (and
it feels really stiff) to get it to shift up. The engine revs quite a bit, but it will always "jerk" into the next gear. Also I notice a similar problem as I ease off the accelerator. As the engine slows, the car will abruptly shift down into the lower gear, which is also "jerky". All these problems occur between 0-60 km/h, there are no problems whatsoever at higher speeds.
I have done the following:
(1) Cleaned the throttle vale with carb cleaner and a toothbrush. (2) Replaced the air filter, spark plugs. (3) Checked levels of transmission fluid, oil, etc. (4) Replaced the EGR valve (5) Inspected the throttle linkage cable
The problem still persist. It usually does this once in every 15 minutes of city driving. I've never had a problem (knock on wood) on highway driving. This happens regardless of the outside temperature, or whether I'm driving on a full tank of gasoline, or an empty one.
Any suggestions would be greatly appreciated.
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
quix22 wrote:

Throttle Position Sensor (TPS). Age & probable mileage... it's time.
Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I think you're right on, Rob!
Replaced the TPS last night, tested it out this morning to work, and there was absolutely no hesitation in the car. It was very smooth as it automatically shifted up and down.
Thank you very much as you saved me a lot of grief and some $$$!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
quix22 wrote:

I'm very glad no one tried to sell you a transmission.
Good luck w/ your Tempo. Ours was the most economical car to drive we ever owned - sold it with 209,000 miles on it.
Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.