Skylark 3.3L chokes.

92 Buick Skylark 3.3L is chugging/choking at any time, but mostly from a dead stop or around the 40-43 mph (lacks power after torque converter engages) but it doesn't happen when changing gears. Its a 3
speed automatic. After third gear, rpms drop to 1500 (normal), then it chokes a bit, and sounds like it runs a little rough when accelerating up a slight incline.
It nearly stalled while moving through the parking lot at a slow speed after start up.
Is ok when driving at 45 mph and above.
I had Advance run codes on it and found a code 27 indicating 3rd gear switch problem. It doesn't make sense to me however. I know the code points to the valve body of the transmission.
I have changed the O2 sensor and plugs.
Could it be the coil pack? Plug wires? Transmission?
any ideas
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@earthlinkremove.net wrote:

Could be a lot of things. Do the usual: check, clean, and/or replace: TPS IAC MAT MAF Throttle body Plug wires (check them while they are HOT! - not over 8k)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@earthlinkremove.net wrote:

Glad it worked out for you. You are very thorough. I usually just stick the sucker hose from my sprayer into a can of xylene and blast everything with the air compressor. Takes off carbon, paint, dirt, and everything. I never thought about taking off the battery cable. That might be a good idea. Paul.
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.