plugs are a little white
 

I am pretty new to the mustang world. I got a 91 GT back in Jan. I changed the plugs when I got it and again about a month ago. It has BBK equal length shorties, BBK h pipe, flowmasters, underdrive pulleys, MSD coil, and a BBK fenderwell mount intake, precision 3.73's, Ram clutch, Pro 5.0 shifter, Accel cap and rotor, Moroso Blue Max wires, fomoco alum. driveshaft, and a few other goodies. I just got an electric fan and fomoco upper control arms. Got the car for 2600 bucks, so I can't complain. Here is the question. I changed the plugs and they are a little too white for my liking. I checked the fuel pressure with vac. 37 w/o vac. 44. I don't really know where to go from here. I have always had vehicles that I just drove, and not monitered. Any help would be appreciated. Also the car doesn't seem to run quite right when you get on it around 2k rpm. From about 2K-3K is seems a little weak. I think it may need a new harmonic balancer. At the same time it runs a little weak it also vibrates through the shifter w/clutch pushed in and in neutral. After that (3K) it runs like a raped ape. The check engine light isn't on either. Thanks in advance for any help.

Is there any vacuum leaks??

Also with a fuel pres. gauge connected, what happens to the FP as you accelerate?? If its dropping then you need a larger pump or new regulator or both, probably the larger pump should solve it though. That would happen since the stock pump wouldn't be able to keep up with the amount of fuel needed.

The pump is loud all the time and when it primes when you turn it on it is awfully loud too. It sounds like it is an aftermarket pump, but the person that had it before me said that it was a factory pump. The fuel pressure regulator is stock as far as I know. I just got the guage last night and haven't had a chance to check it yet. It is the Accel fuel rail mount style.

In my opinion 44psi with vac unhooked from reg should be too much fuel, I run 37# with similar mods and i'm not running lean,
you need PKRWUD to chime in on that!!
As far as your vibration it could be the D.S. was reinstalled in a diffrent position, mine was 90* off after gear swap an shook hard at speed, rotated it till I found best position (least vibration) it's gonna shake some cause the gears throw off some balance,when I've heard others with this problem it vibed at speed like mine. You say yours is at low RPM so??
I know nothing about slipping dampers, agian, not to sound like I'm kissin his butt probably a Ques. for PKRWUD.
Although there are a lot of people here thet know they're stuff!!

Here is some more info that might help out some. I have heard that overly oiled K&N filters can get a MAF sensor pretty clogged with filter oil and can mess up the readings. The car had a heavily oiled K&N on it when I got it. I shortly thereafter changed to the BBK fenderwell mount filter. Can this possibly be the problem. Are the injectors closing too early and not letting enough fuel into the cylinders?

That may cause the problem. Try spraying some contact cleaner into the MAF sensor, then reset the ECU and give it a go. Spray down the sensor 2-3 times, wait in between for 30-60 sec for the last spray down to dry.

Normal electronic contact cleaner availble pretty much at any auto parts store will have some, cost like 3-5 bucks for a can.