Oldsmobile/Buick Repair: 88 cutlass, scan tool, hi lee

Question
i have a 88 cutlass that recently lost the oil fill cap so i replaced it and done a oil change now it will not go over 35 mph any ideas what this could be ?

Answer
Hi Lee,
Is the check engine light on?
The missing cap could have set a fault code, and put the ecm in Limp-In mode.
That is a code that should clear itself, but go to Autozone, and have them read the codes with a scan tool,(Free), and then clear them for you, and see if that is what the code points to, and more importantly, if that fixes your problem.

Van