P1181 transmission help needed

2003 Buick Lesabre 3800 V6 70K only on it. this problem Hard or long shifts it comes and goes, it seems

when the engine is hot normally on a long run it starts with the hard transmission

shifts, same as a P1181 code but no engine check light on yet , some articles say a MAP sensor could cause it

what’s next any suggestions ?.

Years ago the torque converter lockup on a Pontiac I owned would act up when the engine got hot enough. Something similar could be what’s happening to you. Not every fault triggers the check engine light. A good mechanic can probably figure it out by seat of the pants.