Ok So just bought a merc sable ls 24v. for $550
anyhow the problem it has no power if you hold the pedal down in park will only go to maybe 2k. revs up and down. and wont stay running unless foot on brake and gas at same time. 173,678 miles.
before i bout it he changed intake gasket and plugs.
Any ideas? i am new to the merc's thanks.
i was thinking of throttle by-pass valve. but want to hear what you all have to say. thanks again..

 

in case this matters. its a 2001. thank you everyone for welcoming me to your site!

 

My first step would be to try an On-Board Diagnostics (OBD) code reader. Have you done that yet? If so, what codes did you get?

Also, is the engine firing on all cylinders?

And do a manifold vacuum test too. A valve problem would show itself with that.

 

thanks for the info, but i got rid of this car almost a year ago.

 

Oh. I didn't look at he date of your post.
I have some unanswered posts hanging out there too. Maybe they will get answered in a year or two. ;-}