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Discussion Starter · #1 ·
Bottom Line: Mac Cold Air intakes bite the big one!:mad:

Here's the scoop:
I bought my car back in Sept. '01. 40k on the odo, completely bone stock. Within two weeks I bought a Mac cold air kit (inside fenderwell). The day I put it on it was raining real bad in Chicago. Well, after I installed it at my works garage, half-way home the car got hydra-locked (?spelling):mad: . I buddy of mine called his uncle (tow truck driver) and got me home for $50 bucks (1st lucky break). Immediately 2 friends and I starts dissasembling the intake. I found water in the lower intake, the piping, and combustion chamber. We rigged up a wetvac with a smaller hose to suck out the water in the lower intake. Work like a charm (2nd break). Onto the combustion cahambers. With the spark plugs removed, we had a hunch. Crank the car, and if I didn't bend a rod or something really bad, the piston would shoot and water in the cylinder (which there was a least 1 ounce in each cylinder). We cranked it and water fired out of the car and hit the ceiling of my garage, me, a friend, and anything within 20 feet. After a few seconds we began seeing the fuel shooting out. Using a flashlight, it looked as if we got it all out. Put everything back together, voila, it started, died once, started it again, and it purred like a kitten (3rd break).

Fast forward to May '02. Since that day, my car had idling problems coming out of 5th when stopping for a light. It would surge real bad, and sometimes die. Very coming from 5th to idle, and also did it in other gears. It also would get these codes, P0171 and P0174 (system adaptive too lean, bank 1 and 2). I strapped the car to a dyno, and found out it ran very rich (11.2:1 @ 6400rpm):rolleyes:. This would happen every 2-3 weeks after I cleared the codes. I tried to fix it, but just gave up.

Two days ago I decided to put the stock intake back in. The first thing I noticed was that the mass-air meter was horizontal w/ the mac and slightly offset w/ the factory box (when comared to the ground). Next I began contemplating possible velocity changes wich could throw off the air temp. sensor, mass-air meter, and possibly other stuff.

All my theories were true. The car runs beautifully now:). NO idle surge:) . Now I've been told that the mass-air meter has some affect on the A/F ratio(possible 4th break). Who knows, maybe I fixed that to. I have to wait and see for a little while if those codes come back.

If anybody else has similar problems, this could be a possible solution. I have seen many idle surge/stalling threads in the past for the cobras. I hope somebody can benefit from my bad luck.
 

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97cobracoupe,

sorry to hear you've had so much trouble with your MAC CAI. I had one installed a year ago (10,000 miles ago) and have had no trouble. on the other hand, I've only driven in rain twice.

it looks pretty but i'm not sure that it does much of anything for performance.
 

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So, yes. You may have fixed your rich WOT problem too. Your car can add up to 25% fuel as it attempts to hit 14.64:1 a/f ratio while driving normally. In your case it sounds like the CAI was leaning it out more that the EEC could adjust for so it set a MIL. However, any adjustment made for closed loop driving is also applied to WOT. So it was adding fuel to try and richen it up and continued to add fuel at WOT. This is probably why you were rich at WOT.

I wouldn't be surprised if you found your WOT a/f was much better (leaner) now.

Chris
 

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Discussion Starter · #5 ·
I wouldn't be surprised if you found your WOT a/f was much better (leaner) now
I hope so. I'll see what happens when I get a chance to get it on the dyno again. After a little bit more driving time since this post I am happy to say, still no hint of idle surge let alone stalling issues. I'm starting to think I was getting a lot of air turbulence w/ the CAI kit. That's what was causing my idling problems.

sorry to hear you've had so much trouble with your MAC CAI. I had one installed a year ago (10,000 miles ago) and have had no trouble
That just goes to show ya, all cars are different. That's why I use magazine build up cars as a guide, because I may not be able to get the same results they do.
 
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