Sorry to bother you guys but i just had a question/problem with my Magna. I seem to be getting a "lag" in RPM's while the car is running. It started from nowhere and is getting to be a real pain. She is still driveable but i'm just afraid it might seize up on me or something. When the car runs from a standing start it runs ok at the start then when it gets to about 3.5k RPM's it just drops in rpm's to about 1k or under until it feels like the gas pedal is not responding until you floor it wherein the rpm's finally jump back up but the after a while they just do the same thing all over again. Its like i could be travelling at 60-70 kmh and the RPM's are around 2-3k and then you'll see it drop suddenly to 1k rpm and u have to pump the gas and she suddenly responds again. Any idea what this could be? I have taken the car to Autostat Mechanics in Clayton and at first they changed my Airflow sensor but as soon as i picked up my car it just died out while reversing out of the mechanics. So 1 week later and the car is still in the mechanics and they can't seem to figure out whats wrong with it. they have apparently taken the ECU out and sent it to be analyzed. :eeek:

check all your vacuum hoses, the same thing happened to me, and it sounds like the same sought of thing. it took them ages to find and cost me hundreds of dollars and all it was, was a vacuum hose on the wrong bit and come loose. also check all your plugs.

Spark or fuel would be my first guesses. Check plugs and leads, then check fuel pump, fuel filter, air leaks in hoses etc.

Just an update, the guys have the ECU results and its all good nothing coming back as negative. Back to sqaure one. They have tested the injectors and they say those are perfect. I told them to check the vaccum hoses and they said those are fine too. Getting so frustrating.

get them to check the inlet tract for air leaks... hopefully they've got a smoke machine and they can pump some smoke into your plenum and see if it escapes.

that's how they tracked down my leaks when I was only making 8psi.

cheers,
.wook

Try another TPS may be sending the wrong signal to the ecu affecting fuel delivery and ignition.

Regards

Sure its not just the clutch slipping at the high rpm? Sounds like the clutch is good til 3.5K where it slips, then catches again in the lower rpm and repeates cycle...

EDIT: Ohh Its an auto.... disregard my assumption then....

Sure its not just the clutch slipping at the high rpm? Sounds like the clutch is good til 3.5K where it slips, then catches again in the lower rpm and repeates cycle...
If the clutch was slipping it'd be revving out very quickly with no added acceleration, just like if you start to put the clutch in with your foot on the throttle. Sounds like a vacuum leak or a fuel pump problem to me, but I'm no expert.

Sure its not just the clutch slipping at the high rpm? Sounds like the clutch is good til 3.5K where it slips, then catches again in the lower rpm and repeates cycle...

That'd be a weird problem to have in an auto

That'd be a weird problem to have in an auto
I'm guessing he thought it was manual, but the same sort of issue could be had with an auto slipping. It'd do the same as I said above though even if the auto was slipping, it wouldn't die in the **** lol.

well mechanics closed again and still no joy so its officially 1 week and 1 day out now lol. Jeez i wonder what my bill is now? Do i still pay for a mechanics bill if the car is not fixed? LMAO sorry am just going insane without my trusty Magna. :(

Your description made me think of TPS (throttle position sensor).

Would it rev past 3500 OK if you simply put the accelerator to the floor?
You said that revs would die to 1000rpm until you floored it - it sounds to me like the TPS is only recognising the first part of throttle travel or wide open throttle, but nothing in between.

I'm no mechanic, but that's just what I'd check first from your description.

Hope it's fixed very soon for you.
Oggy.

Sounds like fuel delivery. I'd get them to check fuel pressure and more importantly fuel volume with the engine hot.

Well finally got her back and looks like she ingested a bad batch of gas. All sparkies and fuel sensor changed. Injectors cleaned out and all gas lines and gas tank purged. Everything was covered in white gunk. Seems like a couple of the independent fuel places have been tinkering with their gas in my area. $700 all up but i reckon just seeing the end of this saga was well worth it. Thanks for the support guys.

Did you keep the fuel receipt? If you can prove thats what caused it, legally the petrol station has to pay your mechs bill.

Also check this out: http://www.aussiemagna.com/forums/showthread.php?t=70368

$700 all up

Dear God!!! well aleast on the bright side all of those needed to be changed sooner or later