I read the 1.8T troubleshooting guide since I am experiencing poor gas mileage. So I planned on cleaning the MAF and the AIT sensor today. However, I cannot find anything about the AIT sensor anywhere on the forum or in my Bently manual. Can someone please tell me where to find it and how to clean it, I am assuming just use rubbing alcohol. Thanks!

EDIT:

Well I pulled apart the whole airbox apart and I did find where the MAF is located. Holy heck getting that thing apart is tricky! Anyway, I looked in the cylender tune thingy and I could see the MAF sensor hanging down, and it is NOT DIRTY AT ALL. I mean the tube was completely spotless and the sensor looked like it could be new. So I just put it all back together again, because I think I can safely assume that the MAF isn't the problem. What should I check next? Please I need help desperately.

 

#1 best use dielectric spray so you don't touch the sensitive elements

[IMG]local://upfiles/12092/46C9AE51D11C45FDAAA8A5C3462E1911.jpg[/IMG]

edit: appols there I was doing another post on the crank sensor at the same time

 

Thanks avant, but that shows the crank position sensor. I know nothing about that. According to the guide the AIT (or IAT?) sensor is "a small sensor located in the intake manifold just after the throttle body." But I don't know where that is! lol.

 

Can anyone help me out here? Please don't make me beg! lol

 

what kind of mpg are you getting?? Do you use premium?Id start with the basic stuff before dismantleing things that are giving you no idnication that they are bad. If your MAF or any other sensor are faulty youd most likely have a CEL or a fault code stored. Always first check for fault codes, then get your hands dirty. I would consider fuel delivery like a clogged/dirty fuel filter, type of gas being used (use premium) run a fuel system cleaner. Also consider that cooler temps = worse mpg. Consider your driving habbits. Depending on your miles, you might have a lazy 02 sensor that hasnt yet quite totalykicked the bucket. They tend to get lazy over time and cause poor performance/mpg before they completely die or tirgger a CEL or fault code. Check/replace your spark plugs of course. Thats as much help as i can be... Good luck.

 

Thanks onepoint8tee, I can always count on you for good advice.

I just assumed that my MAF might have been dirty because from searching I found that was the most commonly suggested thing and the first thing to check on the troubleshooting guide.

Sorry I guess I was being very vague in my original post and I apologize for that. The last 2 tanks of gas I have been getting 21 mpg at the best. I always use premium gas 92-93. Just the tank before I started getting bad mileage I put fuel SYSTEM cleaner in on about a half tank. I don't get any error codes on the dash or a CEL. The last time I ran a VAG-COM auto scan it didn't come up with anything substantial either.

My driving habbits are AT LEAST 80% highway. I don't floor it all that much, unless I need to.

May need new plugs, I can look into that I guess. Other than that this just isn't all adding up to me.

 

how many miles are on your car? If you dont know when the plugs were replaced last id just do them. Go with ngk BKR6E gapped at .030 if you are stock. I did a lot of highway driving this weekend and got about 25-30mpg. If you are getting 21mpg with 80% highway driving thats not a WHOLE lot to complain about. My city mpg is 20ish or less. I drive conservitiely aggressive if thats even a term. If you ran the fuel system cleaner id replace your plugs next. The bkr6e are copper and need replaced every 10k or less miles but perform way better than plat or irridium and cost about $1.89 each. Like i said though, 20+mpg isnt much to complain about but you probably should be doing better than that if most of your driving is highway. If you have 80k+ miles id replace your 02 sensor even if you have no fault codes or CEL, they get REAL lazy before they die and affect your performance/mpg significantly.

 

I have 54K right now. What exactly does the gapping mean? Is that just the way I buy them? Or a way to put them in? Yeah I think 21 is bad for how many highway miles I put on.

 

So, to confirm, your getting no codes, right?

Are you sure thats what your getting, I mean, how did you calculate the mileage, or are you using the onboard system?

so first, are you sure thats an acurate mileage per gallon, and then if so, what to look at next? I would start next by making sure the air filter is very clean, and then I would look at the trotttle body and clean that, then if your not getting any codes, I would start asking more questions. Like, how is the throttle response? If bad, maybe fuel filter?

Also, plugs could def be a possibility as previously mentioned,so, I would start with these items, and see what you get on the next tank, and see if any codes come up. I have heard O2's can start going bad before they trhrow codes, but IDK for sure.

Let us know if you find anything, or if you get results from any of this.

 

I am not using the onboard system, I wasn't aware the 99.5 came with the onboard mpg calculator. Didn't that start in 2000? Regardless, I just calculate by how many miles I drive divided by how many gallons I put in. Last tank I got barely 300 miles on a tank, and that was with me driving for about 25 miles with the gas light on. And it came out to under 21mpg.

And affimative... no codes at all since I last ran it. I will run it tomorow after work to be sure and post back. When I opened the intake today the filter may have seemed like it was a but dirty. Could try replacing that. Can I get a new air filter anywhere or do I need to get a specific one from the dealer? Same with the plugs, can I get the NGK BKR6E's anywhere? And what does the gap mean?

I am still quite a newb yet to Audis and working on cars in general so I wouldn't know how to clean the throttle body yet, I am learning A LOT very quickly though.

I have always thought the response from the throttle was very poor, but I dismissed some since everyone told me thats the way a stock quattro 1.8T is. I still feel it is very bad though.

Thanks you guys for the support!