Salcov

06 chevy HHR 2.4L 185K miles. Every once in a while after accelerating from a stop, car struggles to catch a gear. Will accelerate fine up to about 25-30 mph then coasts for approximately 3 seconds before catching the next gear. No matter if i floor the accelarator, car still coasts. Code p0700 (trans control sys malfunction) appeares when i check the codes. Anyone else have this problem???

whopper

Yes - give the search tool a try and look for the P0700 error code - and check out the resulting finds such as:

https://www.chevyhhr.net/forums/prob...4-56294/page3/

https://www.chevyhhr.net/forums/prob...7-p0700-54544/

Oldblue

Welcome to the site, check for loose or damaged wires at the TCM , also a loose ground wire at the transmission ground stud. Let's start with the simple things and work up.