Surging idle and no power
96 Thunderbird with a split-port. The car has been great, but just recently has developed a slightly surging idle. By slightly, I mean probably 50-150 RPM change. It makes the car shake a bit and it lurches if the brake is let off enough to gently move forward. Also, there is no power at all upon acceleration...meaning that throughout the RPM range, there is really no acceleration at all.
The only code coming up is P0174.
So, what I have done:
-New O2 sensor, bank 2
-New air filter
-IAC seems to be working, been cleaned not too long ago
-TPS also seems to be functional with a MM
-Checked for vacuum leaks and none found so far
-fuel filter is new in last 5,000 miles
-fuel pump was replaced in September, along with a HG set in December
-PCV is working
-I haven't checked with a gauge, but I have vacuum, although it seems to be a little bit on the low side.
This is also not something related to the transmission. The transmission hasn't given me any problems, and the problem also comes up with a lot of hesitation on the first time I pump the accelerator after it is started. I am usually decent with diagnosing problems like this, but this one has me stumped. Any recommendations?