08-01-10, 12:39 PM
I hope the post is okay here. I did not see anything for 90's STS. I have a 1993 STS with 153k on it. 4.6 NS. I am having a hesitation while driving at lower rpm's. Anywhere from 1500 which is rare to usually around 2k r's. I have tried to nail it down, and best I can tell, it is when accelerating and then taking the foot off the gas, coasting downhill and then hitting the gas again...it starts to "lope" like it can't get out of overdrive or upshift. If I give it more gas it shifts up and takes off fine. So with a heavy foot it goes great, with a light foot at about 2k it hesitates. Engine or tranny? I am assuming tranny because if I keep it in third gear, it never happens. I did replace the vacuum harness about a month ago as it was cracked and brittle and that had no effect. When on cruise control it seems like it is not as rock steady as it used to be at the lower r's so I checked all connections on the vacuum harness and they look good. Some tell me to get the tranny fluid and filter done, others talk about a solonoid. I am mechanical, but when I crawl under there it looks pretty tight less the pan access. Any support appreciated!