mltdwn12

94 Mustang, V-6 with about 30K on a rebuilt long block. 230K on the car. Emissions are due and I'm fighting to get the check engine light out. Searched the site and did some checks. Changed the cam position sensor (with a new plug) and back two O2 sensors (front 2 are about a year old) Also had a code for a short at the speed sensor on the trans. Insulation on the wires was bad, taped it up, speed sensor was put in about a month ago. So did all that and had no check engine for three days, then it came back.

Autozone said I had 171 and 174 codes, lean condition.

I checked fuel pressure today, 30 psi at idle and rev'ing it some. Shut off the motor and it held 30. Over the last year or so I've also changed;
fuel regulator
injectors
computer
MAF
plugs wires & plugs (30k now)
water temp sensor

So this cars check engine light has been on for years even before I got it from my neighbor! Can't find anyone that can keep it off so I started learning the layout of the engine.

I'll start looking for vacuum leaks, but you'd think a leak big enough to throw the lean code would be easy to find (?) Autozone knows a guy with a smoke machine. That may be an option. I'll check intake bolts too I guess. Car was running hot over the summer, put in a new radiator and thermostat, vented 180 degree. Car normally doesn't get over about 170. Today it was at 200 with city driving.

Thoughts? Anyone!!!!!

lincolnshibuya

when was the intake manifold gasket replaced? are those the only codes?
how's the idle sound? rough?

sounds like an intake manifold gasket leak since it's happening on both banks.


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jwog666

its either a vacuum leak, or a MAF sensor that is reading off and causing the pcm to run a lean mix

mltdwn12

Right now those are the only two codes. I guess I'll clean the MAF and look for vacuum leaks for now. If I don't find anything obvious I'll try the smoke test. Thanks to both of you for the input!