1998 Buick Lesabre Misfire Causing 4T65E Limp Mode?

[JesseOBS]

Good Morning, I am sort of at a crossroads here, I had some charging trouble with my 98 which has since been remedied. But in the midst of the charging issues, I noticed my transmission wouldn't downshift if I leaned into the throttle a little bit like it usually would. Instead the engine lugs and the transmission only downshifts one gear if I let off the throttle then it generally goes back into OD. the transmission goes through the gears fine and will downshift If I pull the column down through the gears. This is the early series 2, in the earlier body style (92-97 looking). While putting in the new alternator, we noticed there were a few spark plug wires arcing between each other, causing a negligible misifire at idle, and no misfire under load. It's been really cold lately with some nights dipping well below -10F. I'm not sure what else could be causing this. Any and all help is greatly appreciated.

 

[02LTD2.0]

Have you checked your transmission fluid level in park, engine at normal operating temperature?
Have you ever changed the spark plugs and wires?
Also check the vacuum line to the transmission. It is connected to the modulator which is a round can like thing that helps control the quality of shifts.

 

[JesseOBS]

Have you checked your transmission fluid level in park, engine at normal operating temperature?
Have you ever changed the spark plugs and wires?

I have not in probably a week or so, but whej I checked last it was good, I do the fluid every 25k miles.

 

[02LTD2.0]

....by the way when these transmissions go into limp mode they won't go into overdrive.
You may have a 4T60 tranny and not a 4T65e. They changed to the 4T65e in latter part of 1998.

 

[JesseOBS]

....by the way when these transmissions go into limp mode they won't go into overdrive.
You may have a 4T60 tranny and not a 4T65e. They changed to the 4T65e in latter part of 1998.

Ok, it was bought in 97 so that helps.

 

[02LTD2.0]

If it has a vacuum line running from the throttle body to the transmission then you have a 4T60e. If there's no vacuum line then it's a 4T65e.

 

[JesseOBS]

If it has a vacuum line running from the throttle body to the transmission then you have a 4T60e. If there's no vacuum line then it's a 4T65e.

There is no vaccum line so its a 65

 

[02LTD2.0]

You should have it scanned for transmission codes. A regular consumer level scanner won't see tranny codes. You need to take it to someone with a high-end scanner like a Tech2.

 

[JesseOBS]

Figured it out. Spark plug wires were bad. Kind of annoying as it caused such a fuss, still the nost reliable car I've ever bought. Thanks guys!