redz i'm having the same problem. any update on this? have you found out if the first O2 sensor is out? i swapped my ECU although that got rid of the ECM check engine light, the car is still doing the same thing.

mine is an automatic and it switches gears up and down and turns off randomly multiple times. it will barely idle, when you press the gas the idle goes down below one as if the car is about to turn off. when i put it in park, 20 seconds later the idle goes back up to one as if it's fixing its mistake, or the pressure is going back up.

did you get your coilpack changed? this sh*t was happening to my dad's elantra, CEL would flash for a brief second just like it does in my car and a gear would switch wrong. we took it to a pro shop in florida and they automatically said it was a bad coilpack. they changed that and the elantra runs super fine for a year now. the only difference is that the elantra didn't have any problems with the idle.

if not, then do you really think it's one of the O2 sensors? i had extended mine but didn't get any problems for one year until now... i think it's definitely that evap cannister. now we are in the same family.

 

I had a similar problem with my car (atleast the RPM deal.), But My car was running REALLY rich, like 10 MPG Rich, and It turned out to be my Fuel Pressure Regulator, it would drown my motor till it died.

 

No update as of yet my man. We are going to look at it some this weekend, but won't have much time to do ANYTHING till after the Balloon Fiesta is over.

I removed the first o2 sensor, and it is BLACK. Covered in soot. I was VERY suprised on how easy it came out. I mean it felt like I could have just taken it out by hand, instead of using a o2 sensor tool. With that new user that we have that found out about the Bosch o2 sensor wiring being backwards, I'm planning on trying to swap in...

1. The primary o2 sensor from my car.

2. A brand new o2 sensor from Hyundai.

To see if it fixes the problem. This will also be on the new headers I got for his car (Are your headers cracked too?).



Sounds almost identical.



We swapped the coilpacks from my RD2 and it didn't fix shit.



While possible, I think it's highly improbable. The evap cannister has it's own CEL codes, and has NOTHING to do with the first o2 sensor at all.



Hmm, is it hard to swap out the FPR? I'm wondering if this could be it, as you have a point. The tailpipe is very black, and when we were running it constantly in the garage trying to figure everything out, it smelled VERY rich, AND there was a decent amount of unburnt fuel making it's way through the pipes and onto the cement in my garage.

The thing that I keep thinking of guys, is that this seems to happen on RD1's, with a LOT of miles on them, over 100K.

How do you swap the FPR?

 

thanks redz, i can always count on you. we should stick together on this one. i have a very good mechanic who is going to check out my car tomorrow. if you have any updates, please post them here as i will too so we can finally figure this out once and for all.

i have a bosch O2 sensor too but apparently both of them are sending in readings.

there's tons of black layer across my muffler as well. it gets like that every week. i'm wondering if the Fuel Pressure Regulator is out. but i wouldn't think so since both me and redz' rd1 have the same mods and it all sounds very similar. I am burning more fuel than i should be for sure.

anything i should tell my mechanic for tomorrow? so far i've got:

O2 Sensors
Fuel Pressure Regulator
?Evap Cannister?
Coilpack

 

Well, with the o2 sensor, is it the stock one? The replacement is the one the other guy said was wired wrong for us.

I'd have that checked.

But the FPR, that's easy to fix. It's quite possible too, as there is a rubber diaphragm in there from what I understand, and after lots of miles and lots of heat, it could easily break down.

 

the first one is a stock sensor, but the second sensor is bosch after the cat. i'm going to research a little and see what i can find on the FPR. it could quite possibly be an easy fix, however i'm a little in doubt because before i had my exhaust done nothing ever happened.

the car runs beautifully except for this. i'm discovering new things everyday about high mileage, but hell i'm doing everything i can to take her over 200k.

i'm dropping the car off tomorrow and i will tell you what exactly we're dealing with here so you can get your wifes rd1 fixed too.

thanks.

 

I had almost the same problems and this is what i found out.....It might sound funny but a Very good mechanic told me to do this and I found the problems. 1st get a small propain blow torch with the car running take the torch (with NO FLAME just a lil gas on) take it and run it around everywhere and if the idle goes up you've found your leak . I found out 2 of my fuel injector O-rings were bad and also my intake mani gasket was bad. After replacing runs like a champ!!

 

this is exacly whats happening to my car right now too ive been going at it for a week now cant figure it out.

 

^^^
I'm gonna start working on it next weekend again to try to figure it out. Keep checkin in.



Yeah, it's one way to check for vaccum leaks, and it's PROPANE, not PROPAIN.

I'm going to do the vaccum leak check next weekend, then swap out the FPR if there is no leak.

 

yeah my buddy and i are going over my car tomorrow to....ill post if i find anything.