Tesla ranked No. 27 in reliability, down six spots.
Implementing new tech is listed as a possible reason for numerous lower rankings seen on this year's survey.
The magazine gives more weight to mechanical and safety issues than minor problems such as voice recognition or wind noise. "The suspension issues that some Model S customers experienced primarily in 2017 were due to a supplier-related issue that did not pose any threat to vehicle safety or drivability, and presented itself only when the auto was parked".
The automakers that came out on top are Lexus and Toyota.More news: Federer tested, beats Krajinovic in Swiss Indoors 1st round
It also recommends that "consumers should avoid brand new or redesigned models and wait a year or two until the automaker has had the chance to work out the kinks and headaches that often arise".
The much-discussed Tesla brand ranked in the bottom three vehicle makers in Consumer Reports newest reliability study, Autoblog reported.
"Bulls & Bears" panel discusses how Ford's new ad campaign took aim at rival automakers Tesla, General Motors and Fiat Chrysler.
CR says its reliability ratings "show how well vehicles have held up and the odds that an owner could be inconvenienced by problems and repairs".
Lexus and Toyota continued their dominance on the manufacturer rankings where the two brands posted a one-two finish for the second year in a row. Jeep had mixed results, finishing at No. 22; Chrysler fell seven spots to No. 24; and Ram fared the poorest of the FCA brands, at No. 26. That can hurt reliability as more complexity is added.
It remains to be seen whether the low reliability score will affect Tesla sales. The Model 3 received an "average" grade.