Good catch! Hope that's it.

 

I wish I had caught your post a little sooner I would have ruled cat out right away if it was good once you got it moving at 2000 rpm. And in those years the pressure regulators were know to leak like that and I'm glad you discovered it. Cleaning the MAF sensor would still be a good idea and check your tune up stuff to make sure running rich didn't foul the plugs. Generally the 98 cats didn't plug too much like the later model cats did anyway unless it burned excessive oil or if the intake gasket leaked coolant into the intake ports and coolant was going into the engine.

 

Well that was it. Drove it to town tonight and all is good. My last monte had the fuel regulator go out on it too(96') but it wasnt near this bad. I only noticed it because that one just got hard to start but it ran fine after that. When I pulled the vacuum line off this one, fuel literally was spewing out of the vacuum side of it. Guess I should have just replaced it when I got the car and saved me some headache. My gf's old lumina had the fuel regulator go out on hers too. Just one of those things that go bad on these cars I guess.

I'm SOO relived that's all it was. Was really hoping it wasn't a bad cat. Thanks for all the help on here guys.