[carbon02]

Welcome to the forum-

The P1811 is a very common code and issue with all GM 4T65E transmissions including your Intrigue.

The hard shifting occurs when the transmission goes into high pressure mode to protect itself from slipping.

When the car is shut off it resets the counter for this code. That's the reason why it seemed to go away. Unfortunately it didn't go away, it just didn't happen during that specific driving cycle.

I have a 2000 Intrigue with the P1811 that's currently awaiting a shift kit. I thought I'd try it, just waiting for some help to get it installed. I like many others have payed shops for the pressure control solenoid, only to have this issue come back 10,000 miles latter.

My 2000 Intrigue had this issue at 72,000 and roughly 84,000 miles, so it can hapen with low mileage cars.

I've tried the seafoam transtune as well. It really didn't do much to improve this issue. Didn't really cause any other problems that I noticed either. Seafoam from what I understand is a cleaner, not a seal swelling enhancer. Since it's a Minnesota product, there's lots of people up here that use it, and it's readily avalible at nearly all parts stores. The product for the transmission is different than their engine treatment, so make sure you have the right product if your going to try it.

Good luck and keep us posted with results