Hey,

i have a 1992 Magna TR SE 2.6L 4cylinder wagon auto.

a few weeks ago my car's engine light randomly came on. i knew that wasn't good. the engine started to drop revs, and the accelerator started to get dodgy at responding. meaning it would be revving at 2000, go to 1500, then 1000, i would have my foot flat and it wouldn't do anything, then all of a sudden it would pick up the accelerator and rev high, then drop again. this would cause the engine to cut out.
i managed to get it to the friends place.
i left it for 45 minutes, it ran fine for 15 minutes, but then did the same thing.
i called the RAA, he came and it did the same thing. ran fine for a while, then screwed up.
he ended up putting 4L of oil in (as in, the engine was empty of oil). i do check the oil and water every now and then, and didn't think it would eat all my lovely oil in a few months (whoops).

ended up getting it towed home.

a friend and i tried to diagnose the issue ourselves. we thought it was a fuel issue, and we found that a vacuum pipe from the EFI to the fuel pressure regulator was broken. we replaced it and it seemed to run fine. it ran for 30 minutes straight, twice (as in, on two separate occasions) until it screwed up again. exactly the same thing.

took it to ABBA (a repair shop), and they had it for a few days and couldn't find anything wrong with it (couldn't replicate the problem). they said it might have been because the engine was low on oil, and it had fixed itself.

few days later it screwed up again. i took it back, and it's been there for 2 weeks. this time the problem is occurring for them, so that helps. but they can't figure out what it is. they think its electrical, but don't have any details.

other symptoms include a weird clicking sound from in front of the front passenger seat whenever it drops revs. as in, every time it would drop revs (a few hundred at a time) the clicking sound would occur.

has this happened to anyone else? or does anyone know what could be wrong?

i know its hard to diagnose a problem like this over the internet, but i was hoping maybe someone has come across exactly the same issue.

i took a video of it to show the mechanics, and i thought i might put it on the internet to see if anyone has had the same problem.

http://www.youtube.com/watch?v=Pgb5QAy5Vfc

any help would be much appreciated.
cheers.

sound like a relay??? turning on and off very quickly doesn't sound mechanical to me

dont the mechanics have a diagnostic computer?

You'll find in front of the front passenger is where your ECU or TCU is (cant remember which one) and if its clicking i would assume its on the way out.
I'm sure someone will confirm which one soon enough for you.

ECU and TCU dont have relays in them, Just diode's capacitors and resistors so I doubt the issue is in there.

have you replaced the TPS? I had an issue not long ago with Boozers car where it would idle to 2200-2500RPM in N for no reason at all and stay there and randomly drop down. TPS plug was loose. Maybe check that 1) the plug IS connected and terminals and clean and if not 2) replace it?
That's all I can say, sorry if it's of no help :(

Sounds like the ISC motor needs replacing

sounds like ecu or ecu relay because they have one under the glovebox not in the ecu itself

the mechanics returned it last week saying they replaced the spark plugs, and cleaned the throttle body system. they took it for a 80km drive and couldnt fault it. yesterday it screwed up again.

for clarification, in the video i am trying to keep the revs up to demonstrate how it drops. so the revs arent going crazy by themselves.

i think i might take a look at some of the suggestions people have given me, and will probably end up taking it to an auto electrician, as it seems it is probably electrical.

thanks for the advice so far.

Have you made sure the clip is on the TPS plug? Like just make sure the TPS is plugged in, can be a very easy fix

funny, i was just coming on here to thank you for your earlier recommendation of looking at the TPS. just a bit ago i got my ellerys magna manual thing and had a look at what it is, and if theres any test. i did a resistance test between pins 1 and 4 and it was showing as an open circuit (supposed to be closed with R=3.5k to 6k). i cleaned the pins, still nothing. i hit the TPS with something a few times, voila. we have resistance.

my car went from not starting before i did that, to starting after i did that. so it seems theres a good chance that the TPS is the problem. ill carry around my tools (wirebrush that doubles as a hammer :>), and if it breaks down again, and i do that again, i can be sure thats the problem. is the TPS easy to replace?

once again, thanks for the recommendation. that seems to be the problem. bit annoyed i payed the mechanics $180 for nothing, and they didnt pick that up.