hags1, the K&N was designed with the same diameter intake tube (where the maf is) as the stock system, so the stock maf will still read the same correct volume of air coming in, thus the stock programming doesn't need to be changed. It still allows more air in, giving an increase in performance, but can be done for a couple of hundred, without replacing the stock tune and potentially voiding the warrantee. Some people don't want to risk re-tuning there car, or don't want to spend the extra $3-400 for the tuner and tunes.

chorpeac, the K&N is still an CAI, as much as any other intake is. To really be a true CAI, they would all have to have a clean air path from outside the engine bay, instead of the filter sitting in the corner with a heat shield around it. The only one I've seen is the one that comes with the KB supercharger and the filter sits behind the bumper cover in front of the right front tire.

CAI does not only apply to those systems that require a computer reflash. If you wanted to get a tuner, your K&N would suffice, and tuners like Brenspeed and Bamachips (among others) can set you up with a program that uses the K&N to make even more power, without harming the engine at all. Like someone else said, the handheld tuner would also allow you to read the codes yourself, if you wanted, to see what was going on, and if it were something as simple as a hose coming loose, you could fix it and clear the code without a trip to the dealership.

Good luck, hope it comes back working perfectly.

 

I noticed a couple of things described incorrectly in this thread.

1). The 4.6L 3V V8 does not use an external EGR system. There's no EGR valve or EGR tube running to the exhaust manifold. Instead, the VCT (variable cam timing system) retards/advances the camshafts to reduce emissions and improve gas mileage in the same way as the traditional EGR.

2). There is however, a PCV system and a crankcase breather even in the older Ford V8s. The crankcase breather allows METERED air to enter the crankcase, while the PCV allows crankcase fumes/air to be recirculated into the air intake stream. If you simply unplug the crankcase breather and hook up a K&N style filter on a OBD-II vehicle, you are allowing unmetered air to enter the engine.

3). Anytime you change the air box and filter configuration upstream of the MAF, the air transfer function will change. That means the so-called no-tune K&N FIPK still requires a tune because it no longer uses the panel filter and airbox. One of the founders of SCT once told me NOT to drill a hole (even a small hole) in my airbox for better water drainage and that it would mess with the air transfer function. The air transfer function is pretty much one of the most important things in the calibration. It can affect shifting, air to fuel ratio, and emissions. A screwed up air transfer function can cause an excessively lean condition (detonation) or an excessively rich condition (taking your cats out of commission). The adaptive learning can only do so much to correct for wild changes in the AFR.

 

Ok well for those that are interested, here is what they needed to do.
1. Reprogram PCM
2. Replace Throttle Body
3. Perform BG EGR System, Intake Valves, and Combustion Chamber Decarb
4. BG Decarb
5. Mas Air Flow Sensor service

The cause they told me was that the seal around the throttle body was leaking some air, and that started a chain reaction that caused the rest of it.

The service rep said just like NosferatuVI said, http://forums.bradbarnett.net/showpo...9&postcount=18

I put this on almost a year ago, so I guess it goes to show that I just need to be a little more proactive, and check the tightness of the clamp more often. Luckily, they covered the throttle body and PCM reprogram under warranty. I paid for the decarb and mass air sensor service.

After I got her back, she is running great again. However, I noticed an unusual higher idle rev, and when coming to a stop, the rev took longer to come down to a normal 700-900 rpm range. Almost took it back, but after I drove it around a little while, it started to feel more normal. Could be due to the cleaner?

 

We don't have MAP sensors (and back in the day the MAP sensors had nothing to do with the intake airflow, they were hooked up with a vacuum line).

The throttle bodies and intake plenums DO get a build up of engine oil and carbon due to the oil/fumes from the PCV, since the PCV allows crankcase fumes to enter the air intake stream. The oil also coats the inside of the intake manifold runners. One way of reducing/stopping this oil from getting inside the intake is to use an oil/air separator. I have YET to see any quality units sold for the Mustang/universal application. The Steeda and other units have a polycarbonate bowl that generally isn't rated well below 0F. OEMs like Volkswagen AG have sourced out factory-equipped oil/air separators made of Dupont Zytel Nylon with special filtering elements and have designed it to withstand extremely cold and extremely hot temperatures. They didn't stick an air compressor inline filter and call it a day.

Worn out piston rings can cause excessive crankcase blowby, causing oil and fumes to flow back from the crankcase breather tube and back into the air intake stream.

 

I hope you weren't referring to me about the EGR mis-information as I stated that I hadn't checked out the 4.6 yet and was referring to two motors I was completely familiar with when it came to gunking up an intake, those being the 351 OBD II and the 302 OBD I.
I did pop the hood last night and noticed that as you state, the 4.6 does not have an EGR system. I did see the PCV on the left valve cover which feeds directly into the plenum and a second feed on the right, probably the crank case breather, which is just upstream from the throttle body. I have spent quite a bit of time in the past cleaning the gunk out of upper and lower intake plenums on my trucks. A far cry from the squeeky clean intakes on my 65 Mustang. I still don't like the PCV and the crankcase breather as these contribute to intake fouling but as you stated they are necessary in the metering process and should not be bypassed.

About six months ago I replaced the intake manifold on my wifes '98 Grand Marquis due to a cracked rear hose bib that feeds the heater core. I don't remember seeing an EGR on it either and I remember that the intake looked fairly clean even after 135K miles.

 

I hope you bought a new intake manifold with the aluminum coolant crossover for your wife's 98 Grand Marquis, because the all-plastic intakes will crack! The Panthers (grand marquis, Crown Vic, Town Car, Marauder) all have EGRs and the Throttle body / plenums will get carboned/gunked up within 10,000 miles, but mostly because of the PCV system allowing oil/fumes to get sucked back in. The Lightning and 03-04 Cobra owners are installing aftermarket oil separators, but I haven't seen any units that I would trust in my car. The only one that I've seen which was OEM-quality was the one VW was using on their TDI but they cost quite a lot.

The 4.6 3V V8 in the GT is my first 3V modular engine, so I spent some time snooping around and fondling it. Previously all I've had was the 4.6 2V and 5.4 2V (which are essentially the same, except the blocks are different).

 

I seriously doubt it's that sensitive to changes in airflow. If it was that sensitive to airflow changes, having even a little dust on the stock air filter would wreak havok and lots of S197s would be going back to the dealer for sudden driveability problems.

Also, when 5.0 Magazine did a comparison test of CAIs here's what they said about the K&N (it's from a magazine, though, so take it with a grain of salt):

In their test the K&N posted some good gains without a tune (+18 hp over stock), and got a little more with a tune (+21 hp over stock). Of couse YMMV...