Im new to this 2000 monte SS drove on a trip about 50kms and the check engine light came on and the car has now started shifting erratic betweem all upshifts kind of jerky between shifts and stutters engine sounds fine all levels are good and no overheating, I dont have a code reader yet so havent got any fault codes yet,I was just wondering if any one else has experienced this erratic shifting Thanks

 

hopefully no trans problems but these are known to have that

 

These cars are notorious for tranny issues.

When was the fluid and filter changed in the tranny? if you don't know it wouldn't be a bad idea to service it as they recommend doing this often.

When did you last get gas? with these cars if the gas cap is not put on correctly it will create an air leak in the system causing the check engine light to come on

Possible torque converter issues? the symptoms are similar to a locking torque converter

Without the codes it makes it hard to truly point you in the right direction if you go to a local parts store they may be able to read your codes for free, here is a list of all the codes and what they mean

https://montecarloforum.com/forum/ge...de-list-17144/

The MAF sensor could need cleaning? ensure you use spray designed for doing this as regular carb cleaner will not work

How old is the catalytic converter? these cars are notorious for bad converters from the factory. Does it smell like rotten eggs? if the car is running and you look under and the catalytic converter is red and hot, it is probably time for a new one as it shouldnt' be doing that, and a clogged converter will cause the check engine light to come on as the 02 sensors will be picking up a faulty reading.

 

Get the codes read (most auto parts stores can read a code for free)

the CEL could be putting the car into a fail-safe mode and making it run poorly. We'll know more with a code

 

the code is PO742 TCC stuck on the car has been sitting for a few months,the problem was gone the next day, Ill service the trans and see if that heips has not come back for 2 days so far,will service trans and see what develops

 

So it threw the code and put the transmission into a fail safe mode where it maxed out the line pressures in the PCM.

Could have just been a little fluke.

 

Happened again today thats twice in 3 days,both times after about a 25 mile drive,coming home from my work .ill get a proper fluid change and filter(torque converter included) and see how that helps