CAI and exhaust make car worse?

stargate160

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Apr 15, 2005
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I have a 2000 Mustang V6. I recently installed had a shop install a custom exhaust and today a Cold Air intake. I did these upgrades for the sound, better gas mileage, and a little more hp.

a) The exhaust consists of a Flowmaster series 10 muffler and the addition of another pipe for a "dual exhaust". On first gear, it almost feels like the car lost power when you start moving. It's like it has low back pressure. I don't really notice any HP gain, and gas mileage seemed to actually get a little worse. The sound is good though.

b) I had the CAI installed today (K&N Cold Air Intake) and I have a number of issues. First of all, the check engine light is on all the time now. The car seems to jerk a little when you let the clutch go.

Overall, I feel like both upgrades were a waste of money. I don't see any gains other than the sound. If anything, the performance seems to have dropped.

Was something done wrong? Any ideas or suggestions? I had the car tuned-up about a month ago.
 
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Dunno about A, I think it's probably your mind playing tricks on you.

B, if it's not in there, put the mesh grate before the air sensor. Your computer is thinking you're getting too much air (which it is actually, more than the programmed "ok" amount), and that grate causes a bit of resistance in the air.
 
I had both items installed by a shop, not by myself. I really don't know how Line X installed the Cold Air Intake. They warned me about the check engine light coming on and said something about disconnecting the negative on the car battery and restarting the computer? What's an AIT?

As far as the exhaust goes, they made a Y-pipe which comes out of the muffler and the two ends coming out for a "dual exhaust". It's not a true dual exhaust - the stock Y-pipe with cats wasn't touched. One of the pipes coming out is the stock exhaust pipe, the other one was added by them (same size as stock).

I was wondering, if I have close one of the pipes (so it looks like a dual exhaust but only one pipe actually exhausts gas) - would that help? Someone also told me that the flowmaster series 10 muffler doesn't offer enough resistance for a V6 - is that true?
 
stargate160 said:
I had both items installed by a shop, not by myself. I really don't know how Line X installed the Cold Air Intake. They warned me about the check engine light coming on and said something about disconnecting the negative on the car battery and restarting the computer? What's an AIT?

As far as the exhaust goes, they made a Y-pipe which comes out of the muffler and the two ends coming out for a "dual exhaust". It's not a true dual exhaust - the stock Y-pipe with cats wasn't touched. One of the pipes coming out is the stock exhaust pipe, the other one was added by them (same size as stock).

I was wondering, if I have close one of the pipes (so it looks like a dual exhaust but only one pipe actually exhausts gas) - would that help? Someone also told me that the flowmaster series 10 muffler doesn't offer enough resistance for a V6 - is that true?

So let me get this right. You have one muffler thats hooked to a Y pipe, then 2 pipes with 2 cats coming out? You should have the Y pipe coming out then 2 cats, then 2 mufflers coming out. Sounds like where ever you took it f'd something up.
 
There's one muffler (Flowmaster Series 10). They made a custom Y-shaped pipe that goes into it, so that I can I have a dual exhaust. All they did basically was add the Flowmaster and another pipe which comes out the back of the car. I might have been misleading when I used the word Y-pipe. It's not the Y-pipe with the Cats towards the front of the car. What I was talking about was basically a pipe shaped like a Y that split the exhaust leaving the muffler between the two pipes coming out of the car. I can take a picture if I'm not making sense.

Thanks
 
Drive your car for a few days before you pass judgement on what the mods did for your performance. The ECU will need some time to "learn" the new intake and exhaust flow to optimize the fuel map and take advantage of it.

You won't notice any different performance driving away from the muffler shop- only a different sound.
 
Soccer13en, yes - that's exactly it.

I had the exhaust done about a month ago. The intake was installed today. It's the check engine light that has me worried. I'll give it a few days and see how it goes.
 
New Problem:
Whenever I press the gas now to start moving the car on 1st gear, it jerks like three times before going smoothly. Like:
"Voom Voom Voom" and then it gets normal. It's really weird. The exhaust sounds like it's coughing at first. This happened after I had the K&N CAI installed yesterday.

Disconnecting the battery for 30min and plugging it in only works for awhile. The light still comes on later on again.
 
it really sounds like there is something wrong with the way they installed the CAI like something isnt tightened enough. go back to the shop and ask em to look. kinda sounds like something is loose and more air is getting to the engine than should because when i installed my EBAY one they didnt give me enough clamps so sure enough before i bought more clamps the cai popped off of the intake and the CEL came on and the car would shut off on me everytime i shifted into second. reconnected the CAI, got more clamps, CEL turned off on its own, no problems. i didnt notice a huge boost in power either but definitly not a loss and the CAI makes a sweet little whoosh sound lol. good luck man
 
Well, my first answer to that jerking motion would be BURNT OUT CLUTCH!! but seeing as how it didnt happen until you did your intake/exhaust I'd say it's got to be a sensor of some sort. I don't think a leak will create as big a problem as that. Could be something as simple as a loose coupling on your intake somewhere. Check you PCV valve connections, idle-air control connections, MAF, and the one sensor between your MAF and TB (which I think is called the IAC). Make sure they are all inside the air tract and exposed. I could ramble on and on, but this sounds like a simple problem that has been overlooked. Could even be defective parts? I would rule you exhuast out (since that just deals with O2 sensors and emissions) and focus on the intake. If thats not the case..try looking into your O2 sensors for...something... :shrug:
 
I think there's a Autozone near the place I had the CAI installed at, so I'll go there tomorrow. But I disconnected the battery today for 30min and put it back in. I can't even describe it. When you put the car in gear and press the gas, it starts making a coughing sound like it's going to die. You have to get it up to 3-4k rpm just to keep it from stalling. And even then the car drove sluggish and jerky. Maybe it wasn't getting enough air?

Later, after letting the car run for awhile and driving it, it seems to be back to the way it was. I want to say it drives fine right now, but I'll have to drive it a bit longer to say that. Maybe it needed time to adjust the sensors or something? But the CEL came back on now.

I really don't know. It has something to do with the CAI. Or maybe the shop that installed it messed something else up while installing the CAI? I'll go there tomorrow and update you guys on what they tell me or do.
 
i would take it back to the shop that did the install as opposed to autozone just since they installed it and your car shouldnt be having these problems. exhaust is ruled out because the way you had yours done with just one muffler really wouldnt affect anything. i have a feeling that they forgot to plug something back into the CAI or something shook loose. honestly i think you could take out the CAI and reinstall it yourself but since a shop did it then have them fix it. good luck
 
Well I went back to that place to have them check it out, and they said there was nothing wrong as far as installation. He tweaked one of the sensors and restarted the computer. It worked for awhile. The car was driving amazingly. But then the same crap started again. The CEL light came back on and the car is driving like crap again. I don't understand what's wrong. Because I bought this CAI online, they can't do much. They said it's installed properly and they checked it twice. Unless something comes up, I plan on going back tomorrow and having them install my stock airbox back. I'll probably up the K&N CAI on ebay and cut my loses. I'm seriously disappointed in it, it cost like $200 + $50 installation and made my car suck.
 
i dont knnow what to tell you man other than if your CAI is truely installed correctly and your cars not running right then you have a pretty rare case. tons of people(like myself) are running CAI's with zero problems and most of us installed them ourselves. i hope the $50 install was part of the exhaust intsall because it should not cost that kind of money for a 15 minute CAI install.
 
Okay, well you got taken on everything.

They fabbed up a terrible exhaust setup and made you pay for the flowmaster to boot. Do you have one muffler or two now?

Second, it does sound like there is extra air getting in somewhere. Check all the connections on the CAI. That will be your problem, I am willing to bet on it.

The IAT (IAC) is the Air Intake Temperature. It is between the MAF (Mass Air Sensor) and teh Throttle body. IF they messed that up that could be your problem.

Go to autozone and get the code read. It is free and will help pinpoint the problem.

I would also go back to teh shop and ask for my money back.
 
They did not do the exhaust. I had the exhaust done like a month ago by a muffler shop. I don't understand one thing. I've been to atleast 6 different shops and asked them to install the exhaust. Midas said it's $65/hr and will take them 2 hours to install = $130. Magic Merlin shop said labor is $135. Magic Muffler is $88. And some others that ranged from $65-185. All of them said it would take about 1-2 hours to install. This place (Line X) was the cheapest ($50) and installation was a little over 45min.

I could not find a cheaper place, and Line X seemed to deal with air filters - I figured they knew what they were doing. But because I did not buy the part from them, they won't return the money. I took the car back to them twice, they checked and said everything is installed properly. I don't know what to say. Most reviews I read of the CAI said it's an easy install and takes about 30min. I figured the first few shops were trying to rip me off, but all of them said it's about an hour or more installation. I figured there was more to it for my specific type of CAI and car maybe.

I will go get the code checked out and see where that leads me.
 
Okay, what kind of CAI, manufacture and why did you not do it yourself?

You could have gotten a MAC "Y" Pipe Dual exhaust kit for around 300 bucks. I know that you were probably on a strict budget but still what they did to your exhaust is terrible.