Car is a 1999 Honda Accord EX automatic with 119k
It starting stumbling almost stalling) at low idle all of a sudden and has thrown a check engine light (same one you'd check if the gas cap is loose- it hink it's 1166-1167).. the plugs have recently been changed with NGK's
The engine was recently pressure washed about 300 miles ago.. these symptoms started about 100 miles ago..

Also if you have any insight on the problem, let me know

 

What CEL is that, fuel system efficiency or something like that?

 

P1166 - Long Term Fuel Trim Additive Air; Bank 1; Range 2; System too Rich
P1167 - Primary O2 sensor heating circuit

Replace your primary O2 sensor

 

ahhh.. thanks a lot..
will check further into it..

 

120k miles is a little early usually but not uncommon..

 

You must be thinking Cat. converter...
Oxygen sensor change interval is like 60,000 miles

I know these go out on BMW's like clock work, probably due to a slightly richer mix from the factory..

 

very true. o2 sensors can go bad quickly if the conditions are right.

change it and see how that does