03 350z losing power at high rpm code p0507
 

I have had my 03 350z touring about 5 months and a few months ago I was driving on the freeway and got on the accl pretty hard when the rpm dropped from 6k to 4k and would go back and forth while i was i was at higher rpm. It ended up throwing code p0305 crank position sensor. Long story short I bought a nismo coi that had a maf sensor on it already and after putting the intake in i didnt have the problem again and assumed my maf was bad. About a month ago my cel came on again but didn't affect anything that i could notice. It went away after a week when my z began to lose power at high rpm. If i hit the accl hard past 3k it would randomly lose power and could barely get past 5-6k in any gear. If i eased up the rpm's rather that gun it I could get better performance but still didn't run right. I then got code p0305 again and I replaced the crank position sensor. After that I drove around for a bit and now am getting p0507 even after and idle relearn. Idle seems fine but I still can barely get past 5k rpm in any gear. I clear the code and it comes right back. Any help is much appreciated.

sorry i'm a n00b and posted this in the wrong area. Reposted in tech.

Thanks for responding. I went through all of these steps and still have the issue.I think there may be a vacuum leak because I notice a hiss sound when I lose power. I will check that tomorrow and post back.

update
 

finally got around to working on this.

I swapped the throttle chamber and maf with my buddy and I still had the same issue. I took it to the dealer and the tech there was able to get the idle relearn to stick by unplugging three of the spark plugs first then doing the re-learn. Guess the relearn doesn't stick if the rpm is over 1500 at idle or something like that. After about an hour and half of work he said that it seems like the ecm is bad. Only charged me $40 which was cool. I'm going to pick one up off ebay and take it back to get my keys programmed. I'll post back with an update

Tonman, Did you get the ECM? If so, did it fix it?

sorry haven't gotten back til now. I just got back from the dealer and the ecm that I got from a friend is completely dead. I am search of another as we speak. I will report back after.

picked up an ECM from the marketplace here and just had it installed! Happy to say my Z is back to normal and man does it feel good!

Just a quick summary of what I noticed. As the ecm started to go bad I would randomly lose power at higher rpm's. Once it completely went I could barely get past 3-4k in any gear. Another thing I noticed was that the cruise control would not set. I could turn it on but when I would set it, either the set would begin to flash or the cruise light would go out all together.

I think the Idle issue was just a coincidence personally and not an indication but I'm not sure.

Do you think it had anything to do with the sensors, or was it the ECM the whole time?

rarely in the past, I have noticed that under acceleration it would "hiccup" just stutter for a second during the climb. No big deal, kinda thought it was the clutch or something.

well this morning coming into work, it will behave for maybe the first 15-20% of the throttle, but if I push the peddle farther than that, its like it wont open up. 30% or 100% throttle, same acceleration.

Idles fine, but even in first gear, it was crawling past 5k RPM.

Ill try the idle reset laid out in the other thread. Guess my first stop needs to be pepboys or something to get a code. There is no CEL or anything else out of place.

I think my issue was the ecm the whole time. My issues first started with the occasional hiccup during acceleration like you're talking about. Thought maybe mafs was to blame or my coa sucked up some water but then it did it again on a dry day and I swapped mafs as well.

Do you have cruise control? If say are you able to set it?

I tried unplugging the MAF, someone told me that if the MAF was bad, that unplugging it might result in an improvement. Well that certainly wasnt the case, just went into full limp mode, redlined at like 1500RPM, so it didnt tell me much of anything.

I did just take it out for a spin, tried to set the speed control, at first, nothing happened, then after a few seconds the set light blinked, so I guess it is exactly what you encountered.

I have a obdII scanner to be delivered today, Ill check the code, but it sounds like Im headed for a new ECM.

well, no codes... Ive never gotten a CEL, so that might not be odd :/

I also reset the ECM this morning, so maybe that would have cleared any codes anyway, Ill drive it around a bit and see if I can make something pop up.

seems like the ECM is about 300 bucks, and Ill need to get the dealer or a locksmith reprogram this thing as well. I wish I could be more certain.

i picked one up for $100 (got lucky) You should be able to find one for around $200 pretty easily. I put up a wtb and got a bunch of responses.

Also took apart the dash so the ecm was easily accessible for the dealer and they only charged me for an hour labor to swap and program it.

GL

curious, but was your power spotty?

been testing it, and have found that while the power is generally not there, it will kick in with spurts of full power, kind of how in the past it rarely would lose power for a tick, now it gives power the same way.

Ill have to let the nissan dealer take a look at it unfortunately, I cant buy an ECM without any idea if it will fix it. hopefully they can narrow it down and make sure Im not replacing things that arent broken.

what you're describing is exactly what happened to me as well. I would randomly get "spurts" of power, especially in lower gears. Have the dealer check it out but i would put my money on the ecm.

Ares, what have you done to the car recently? Mod's, maintenance, odd driving condition?

nothing, havent modified it in years. no recent gas fillup either.

Its been at the dealer since this morning, they say theyve spent all day trying to figure out whats wrong with it, called to NNA they say. still searching...

I told them I thought it was the ecm, youd think theyd test that right off, but I dont know.

24 hours later they came back with the problem.

The aftermarket tires...

Volk rims and bridgestone rubber 245 front 295 back. Been on the car for 8 of 9 years.

I told them to keep looking. I swear...

That could cause a problem depending on the model (Car) and diameter of tires but if they've been on that long its not likely it.

yeah, its an 03 touring, but the diameter is as close to original as you can get within the limits of tire sizing. Plus it is nothing new, been on there for years and years.

I wanted to tell the guy, if you want to say it is the tires, find a set of stock tires, put them on the car, let me drive it around and see that everything is fine.

they are taking another look now, but if he has no answers on monday, I will ask them to do that.