Hesitation between idle and 2000 rpm and idle surge

[OblivioAssebit]

Hey everyone. I looked all over all the forums and couldnt find anything about this problem. I had an incredible oil leak so instead of paying someone to fix 1 gasket I pulled my motor and redid all my gaskets, head and block. I added a new clutch and some other small things. A week after i got it running it started to bog between idle and 2000-2500 rpm. I've changed plugs, wires, and my fuel filter, but nothing has changed. Fuel pump maybe? I also have an idle surge from 800-1200 with all new vacuum hoses. I heard it may be the BISS but i dont have one of those on a 420a. Anyone have any suggestions.

 

[420aNEWB]

mine had a similar problem when was the last time you changed your fuel filter?

 

[OblivioAssebit]

About 16 hours ago. Its brand new.

 

[Zardoz]

I'd do a fuel pressure check, not sure if Auto-zone or someone else might have that at on a loaner tool program. Kinda odd though, I would think if the fuel pump were petering out that you'd lose the top end, but on the other hand if the pressure regulator were acting up you might get both stated problems.

I'd also check the IAC and make sure it's not clogged and also check it with an ohmmeter (forget the range off the top of my head but if you have a Chilton's or a Haynes it'll have the info).