weird problem between 30-80mph my engine will start missing I have no CEL, however I did just get my transmission rebuilt I took it back to get reassured my tranny wasnt bad and it turns out to be a engine miss rather than a slip... what could it be

 

Need more info It could be any number of things.

What engine is your car?
How many miles?
Whens the last time your did a tune up?
Have you checked your spark plugs?

 

Without more info (as stated above) could be any list of things:
- Bad plugs/wires
- A wire arcing
- Failing Coil (not common, but has happened)
- Bad injector
- Failing fuel regulator
- Failing fuel pump
- Failing CAT

If you have access to a scan tool that can give some sensor reads and such, those ones can typically read cylinder mis-fire data. It may tell you which cylinders are mis-firing (even without a code). That can help pin point the issue (if it's one or two cylinders, limits the issue).

 

According to his username, he's got an L67. Regardless OP, check out what has been mentioned above and let us know what you found.

 

When is the last time the fuel and air filter were replaced and the MAF sensor cleaned? Those could cause the engine to hesitate (which wouldn't set a code) but if the engine was actually misfiring a code would be set after two occurrences.

 

It only does it when the engine temp reaches around 180-190 and it doesnt help that the texas heat is around 110 right now... I'm leaning towards a overheating coil?
When i bought the car used the dealer changed all the plugs and wires

 

I cleaned the MAF sensor when i got bank 1 too lean and that solved the CEL i got that awhile back before this started happening

 

have that cat checked, that is kinda what mine was doing.....thought I had a fuel or spark miss with no codes.....but it was a clogged cat

 

Update*
After driving for awhile no missing or weird shifting at all after cleaning my MAF sensor again the light came on for a p0741 tcc stuck off... should i take it back or should i see if its just due to the break in period i havent been hotroddin... i had my tranny rebuild in the last car and this code came on after driving a long way but after about 2000 miles the code never came on again