Just had Synthetic oil replace the regular oil in my mustang bullitt at about 67000 miles. And every since it feels alot weaker, the response went down, and it feels like its slipping. Should i change back to reg oil????

 

I cannot imagine that synthetic oil caused that. Did you do anything else?

 

Did you over fill the oil? What viscosity synthetic did you use? ..what viscosity regular oil WERE you using??

 

i switch to mobile 1 synthetic and i was told that after use of regular oil your seals get formed to it, and if you change to synthetic its alot thinner and causes slippage. but no i didnt do anything else.

 

I've been a mechanic all my life. I think those are old wive's tales.
Synthetic oils are much less likely to be damaged and carbonize due to heat problems in an engine. Their viscosity is more stable and they flow better when cold. They also leave a better film behind to protect on cold start ups. I have been using synthetics for twenty years myself and feel they're worth it. When my new Mustang gets up to 5k miles, it'll get synthetics.

In an old engine that has a lot of carbon build up, the synthetic oil can actually dissolve the carbon and then hold it in suspension. Many people seem to think it's "dirty oil" and don't realize it is cleaning their engine. Because it flows better than regular oil, if you have any seals or gaskets in questionable condition your weeps and leaks will get worse using synthetics.

Did you accidentally over fill? That can drag your crank and cause problems.

 

Synthetic oil is supposed to make things a bit slicker...what are you really getting at here?