Hesitation, bucking. Even after IAC change

[vr4operator]

Title says it all. Put a brand new IAC in and its actually worse. The idle went from being somewhat high at 900-1100, to around 1500rpms at temp. Still hesitates when starting out and bucks when you add power. totally lost where to go now.
Installed walpro 255 and stock fuel filter 5-8k miles ago.

Looks like all the lines are on and i don't see anything abnormal other than what i've already described. well, eating fuel like crazy...

Any insight is appreciated. Thanks,

Butch

[Bigmac]

Mass air sensor ..mine did the same thing

[venik]

plugs, wires, boost leak, coils, PTU, ECU

[vr4operator]

Originally Posted by Bigmac

Mass air sensor ..mine did the same thing

How do I check this one?

Originally Posted by venik

plugs, wires, boost leak, coils, PTU, ECU

Plugs have less than 4k on them and I inspected the front bank and they were good. Wires are about 15k old and they are Accels. Boost leak, maybe, but I'm only running 11psi and no matter how hard or easy I go on accelerating, it bucks. Coils are an unknown, probably original, but the PTU and ECU were checked about 5k ago (I thought the caps had gone bad, so it was inspected).

Butch

[Polygon]

Originally Posted by vr4operator

How do I check this one?

If it isn't throwing a code try unplugging it and seeing if the symptoms are the same. If so, you need a new MAS.

Also, it will throw a code when you unplug it.