my 98 gt is throwing a check engine code. I got it scand at auto zone right and left bank lean. Have after market tb and mass air. Never was a problem before. Have 29 psi fuel pressure at idle. Want to know what it sould be. Or where else to look with out throwin parts at it.
A lot of times it is a leak in an intake gasket or a vacuum line that is cracked and leaking. This is showing on both sides, so the air leak is central to the intake somehow. Generally to the plenum.
BTW, I got the same codes for my 2000 Ford Explorer. I reset it a month ago, and it hasn’t returned yet. Just some food for thought.
1998 was the first year Ford used a returnless fuel system on the Mustang, it did have issues with fuel pressure regulators going bad. You may want to check that out. Also have you had your car tuned for the bigger TB and MAF sensor? Sometimes that can be an issue, but it usually shows up when you added bigger injectors.
BTW the best bang for the buck upgrade for these cars is the P.I. intake/heads combo. You can pick up a set of heads and an intake manifold. They can be found for cheap at most junkyards, and will easily net you a 45-55 HP gain.
The Test Step HC2 states fuel pressure should be 35 to 40 psi: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?fromSearchPage=true&pageId=0900c15280250e6d&partName=Fuel+Pump&partId=0900c15280250e6d A lower fuel pressure could make the engine run lean. Use a Haynes, or Chilton’s repair manual to perform the fuel pressure checks. You’ll need a Ford Schrader valve fuel hose adapter (ebay.com) to use with a fuel pressure test gauge. Ready to do some testing?
Keep in mind that with PI heads You have to run premium fuel due to increased compression.
I’ve never, ever heard that.