Okay here's the deal my car didn't start one day like 2 months ago so I had it towed to nearest Dealership. I honestly thought I was gonna need a new engine again because it's been replaced once summer of 2010(at 85k miles). But dealership told me it was bad coils so I let them replace it for around 900 dollars. They also asked me if I wanted to change the spark plugs/plug wires because they didn't look very great(even though it was replaced with my new engine little more than a year ago) I said no thanks and replaced them by ordering them through amazon and diy section. Since then I had no problem with the car except bad gas mileage!!! since the new engine(summer of 2010) I've been getting like 21~22 high way and 17-18 city but through past 3~4 months or so it's been decreasing from 16-15 to 14-13 now I'm half way between half tank line and 1/4 line and trip measurement says 120miles so I'm sure I'm gonna need to fill up around 170 miles which would come out to 13 mpg ish. There isn't any difference in my driving(distance or the way I drive, I drive it normally shifting between 3k~4.5k and redline at least once a day) because I'm a student at Texas A&M and it's just school-home daily routine except going back home during breaks.

after coil change CEL was still on and dealership told me they forgot to reset it and it should go off in short time. But it never did so I thought it could've been the spark plugs/wires Even after replacing them the CEL was on so I went back to the dealership and they told me there's problem with my AEM Cold air intake leaking something (i think they said it's air?) and they'd need around 1-3 hours diagnosing my car would would cost around 80 bucks if they find the problem within 1 hour and 250 if they find it in 3 hours. I told them I would be back and came to forum doing some research.

I ended up cleaning MAF, replacing cabin filter, fixed the fish tank tail light problem, and got an oil change.

(oh and after I changed my coils I also got a new battery from autozone even though old one was also replaced during engine replacement last year.)

After replacing battery the car had problem staying idle for the first time(it never did that last time but dealer said it's because they "save" the program and reinstall when they replace the battery blah blah) so I had trouble keeping my car on... but it fixed itself after ECU reset thing that involves lot of pressing on brake and like 10 driving cycles(IDK how i'm still alive). BTW battery change only took like 5 min which questions me why my car lost its memory on "where to idle"....

Sooo what should I do guys
I honestly think if AEM CAI is the problem I'd rather buy a new one and install if i had to pay almost 300 dollars to "diagnose the problem".
Also I've been really careful about redlining and warming up the car before trip and before turning her off.
Would changing Cold air intake filter do anything? is that even possible? lol

Also when I did that flash(brake pedal thingie) do you think the car might've lost new update on M flash or L flash or whatever newest one is and I just need flash it at the dealer?

anyways I'm about to give up on my car I just need it to roll until my graduation next may/august and I'm off to a new car(even though new rx8 R3 sounds tempting but I want better gas mileage....).


My car is 2004 RX8 M/T
AEM CAI
Tanabe Hyper Medallion Exhaust
Clear corners
Axial flow short shifter
Drilled and Slotted Rotors
Painted Calipers
rear/front Strut bars

ps. my car has weird noise while braking to a stop like "grunk grunk grunk grunk"(sorry for my lack of description) and when I ride around bad road with bumps(grr @ College Station Roads) I hear clunking noise under the car(i'm assuming it's coming from my brakes). I told my dealer about it but all they could find was that my front passenger brake caliper is little loose due to that one long bolt (I think called caliper bolt pin or whatever) and told me to try caliper bolt guide pin kit(I think) at autozone.

I tried brake-check and they told me it's my suspension that's causing the problem and told me it would cost 500+ for a replacement. Also I've been hearing loud Clicking sound on my left front wheel when I start braking which Brake check guy told me it's my U-joint or whatever and it'd cost over a grand to fix....

please help guys I'd appreciate any input!

 

oh now it's at 98k miles btw!

 

oh yeah and also rear o2 sensor was replaced with coils which was why it was 900 dollars i think lol

 

Not too sure about the 8 but I know on few of other cars I've run into this problem before. I was able to fix it by cleaning out the throttle body and butterfly. A gunky layer of carbon gets built up. Over time this carbon builds up slowly and the computer learns to compensate. However when you replace the battery it goes back to a default mode and "forgets" that the carbon had built up and cannot deal with it so quickly. Usually a clean shop rag and some carb cleaner will do the trick.

 

The "grunk grunk" noise may be your pads are worn , loosen the wheel nuts a little, jack the car up and support with stands, rip the wheel off and take a look to see how much material is left on your pads, if its been happening for a while, your rotor's will be toast as well. We dont have uni's in the front. When was the last air filter change ? The noise underneath may be your cat is coming apart internally, while you have the car up on stands, give the cat a few good thumps to check if it rattles.

 

should I do it through the dealership because the technician told me how it could mess up the engine if not done properly. Carb cleaning(from what I researched) required taking out belts and such or is just those carbon cleaner thingie at autozone would do it? like seafoam or those mazda zoom zoom cleaner like nycgps

 

Hm weird I replaced my pads 4~5 months ago or so, I recently checked(around 3~4 weeks ago) my front pad and it seemed like it had lots of pads in them I replaced rotor with them so if it's pads fault I guess I need to get a new rotor :/

And also should I replace my AEM dryflow air filter? I havent replaced it and thought it had like lifetime warranty so I didn't think it would cause a problem since it was installed like year and half ago!

When my car was lifted at the dealership they didn't say anything about my cat being loose they said all was good except few clips on my fuel line thing was coming apart so they replaced that.

for the Clicking noise maybe it's the driveshaft thingie? i mean it makes sense where if i apply brake the drive shaft ball can't take the pressure and clicks once? cuz it only clicks once only.

 

Not sure what belts you are talking about. The stuff im talking about is just geraric "carburetor and throttle body cleaner" available at any car parts store. its a spray can. The way I do it is spray it on the rag and wipe out the throttle body. If you're nervous about doing it yourself then don't. Perhaps see if the dealer will do it next time you are in for service.

 

Hong, if you have replaced the pads and rotors recently, it could also be a wheel bearing going bad, its difficult to diagnose without hearing the noise.

 

oh throttle body, I was thinking SSV lol.
taking out SSV took lots of steps so I would be nervous.... but if it's just throttle body I don't think I'll have lots of problem taking it out. I was talking about the Engine belts that needs to be loosen if I want to take out the SSV.

I will definitely clean out the throttle body after my microbiology&genetics final tomorrow!

 

Like I said "grunk grunk grunk" noise (according to brake stop guy) might be coming from the old Struts he said something about my car going up and down when coming to a stop because the weight is tilted toward front then back and front then back. But when I sat on front of my car(front sides) and got up it just bounced back without it going up and down (which i hear is how to diagnose bad struts) I guess it could be the struts....