S10 has a rough idle and sounds like intermitend misfires. Changed plugs+ wires, checked exhaust flow, and changed the fuel filter. Owner stated the a small amount of deisel was put in tank on mistake. Any suggestions?
I would drain the tank, and then put freash gas in and disconnect the fuel lines and pump fuel into a bucket to clean the lines. See how she does on real gas and then you can see if you have a problem.
If you still have a problem, I would check the fuel pressure and see if the pump is working properly. If you have good fuel, then it could be an injector, ignition or timing. Pretty much wide open. Are there any engine codes in the computer?