BLKsteeda

I have an 01 GT with all the bolt-ons including cams. I have been having an occasional fuel pressure problem and I'm not quite sure what the problem is. On occasion when I "get on it" as I press the gas pedal my fuel pressure gauge starts dropping as I am pressing the gas...eventually dropping all the way down to 0 at about 5000rpm and then the car starts to bog. The problem is not there all the time. I have already had the fuel filter replaced and was curious where I should start next. I think I am going to go ahead and replace the fuel pump to rule that problem out. Under normal driving the car runs and idles fine...but the fuel pressure never seems to read a consistent pressure...it is constantly bouncing around between 20 - 40 and never goes above 40. Any suggestions?

mdvaldosta

dude if your pressure is dropping then your running lean! don't get on it with low fuel pressure unless you want to build another engine - get that fixed, I hope its not too late. Pump would be where to start

Phirantes

Hey md can you explain exactly why running lean is bad... i know it may blow up your engine or something especially if your blown but physically what does it do?

mdvaldosta

lean = more power (in moderation) but the extra fuel helps keep the engine cool, especially the pistons. Thats why at cruising and part throttle engines run a higher a/f (like 15 or 16 :1) and at WOT its reduced (to about 13.1 : 1 on a NA motor), the extra fuel is needed for more detonation resistance. Run too lean and you won't be left with much of a piston, run even more lean and the car won't run at all (which isn't as bad).

Birdieman4

If your fuel pressure is dropping under load, even a little bit, it's almost certainly your fuel pump. If you replace it make sure you get a 255l/hr pump. Steeda's is good. Either way, don't push it hard until you get a new pump.

BLKsteeda

I'm having the fuel pump replaced this week by Steeda. They have an upgraded fuel pump for the 99 and up stangs. Hopefully that will take care of the problem. If that doesn't should I look towards the injectors next or possibly could there be a problem with the fuel pressure sensor? Would it be good to have the car re-tuned with he larger fuel pump?

Birdieman4

That new pump, almost certainly, will take care of the problem. If it doesn't(it will) cross that bridge when you get to it.