common vacuum leak areas (p0171/0174)

[Bangster]

1997 with 120k miles.

Emissions test is due by 1/31, and 1/6 the check engine light comes on ::sigh:: System Too Lean (Bank 1/2)

It currently isn't on, but pending codes again are p0171 and p0174 (and p1000). I reset the CEL because I swapped in a new coil to fix a misfire, and also ran it with the MAF disconnected when I cleared the TB with it running, so had MAF and IAT codes.

I also hear what I think is a new very loud sucking sound (it has always been noisier than my 97 Cougar and 2000 Grand Marquis, but the sucking sound seems louder now).

I cleaned the MAF and the throttle body with some spray. The crazy rubber seal for the hard plastic air intake tube to the throttle body isn't in great shape, but I wrapped that with an bike tire tube and that didn't help.

 

[slowmkviii]

There are not very many vacuum line on a gen 2 but the in my experience the t and the two lines off the t going into the upper intake fail first.
Also there is a small plug on the bottom of the throttle body that has been knowen to fall out.

 

[Bangster]

I would say there are 30 times the vacuum lines on my 97 Mark VIII than on my 2000 Grand Marquis or my 97 Cougar. The one to the PCV are weathered, the T looks okay, the one on the passenger side to the valve cover is solid. There are so many of the hard plastic ones, FPR, the pressure surge thingy, EVR, EGR, whatever is mounted in front of the crank pulley, etc.

Propane and starter fluid sprayed around them all I haven't had it surge or change idle.

I also replaced the fuel filter, as the sound might just be normal.

http://youtu.be/ZFKzcN6Ko2w

 

[termin8r]

Had the same codes on my 97. Replaced the iac motor. fixed.

 

[Bangster]

I was looking at the IAC. I am not sure how it works on the Mark. On my other 4.6 cars it has a hose to the intake so it can get filtered metered air, but on the Mark it just sits on top, no hose to draw air in. Is it somehow done internally to the throttle body?

 

[Sapperfire]

. I am not sure how it works on the Mark.

It opens and closes, like all the other ones

 

[Hot*Mk8]

I am currently dealing with the same excessive vacuum sounding noise and have a leak in the front bearing on the driver's side IMRC. It has caused a seriously fluctuating idle at operating temp to the point of occasionally stalling on low RPM turns. My solution due to the complete lack of replacement parts is IMMR deletes, 3.73 with Trac-Loc, and a tune from Lonnie. I don't want to have to go in once a year and grease deteriorating bearings.

 

[ford nut]

I am currently dealing with the same excessive vacuum sounding noise and have a leak in the front bearing on the driver's side IMRC. It has caused a seriously fluctuating idle at operating temp to the point of occasionally stalling on low RPM turns. My solution due to the complete lack of replacement parts is IMMR deletes, 3.73 with Trac-Loc, and a tune from Lonnie. I don't want to have to go in once a year and grease deteriorating bearings.

It is a sealed bearing, I have a few laying around I do believe.

If you want to delete the runners, I would go with more stall in the convertor, and cobra intake, and deeper gears... 4.10s.

Even with that its debatable if you should delete them.