Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Silver-Fox

macrumors 65816
Original poster
Jan 8, 2007
1,091
2
England
Hi

I have searched the web etc and cant find anything, i recently got a toyota corolla 1.3 1998, only done 37,000 miles, today i started the car up and let it run for a bit, then i realised the revs dropped below 1000 and the car started shuddering quite bad any ideas?

I know quite random but i wondered if any car experts here to help :D

Cheers
 
what do you mean by below 1000? because most cars will idle around 800. if its quite a bit below that it may be your throttle position sensor.
 
A TPS error would probably cause the car to rev, not shudder...

An automatic at idle will typically idle between 500-800rpm...
 
sorry i was thinking of the wrong part, have the idle control motor checked. had what sounds like the same issue and that is what fixed it.
 
Further thoughts:

1. if the car is fuel injected, run some injector cleaner through it. Could be a plugged injector.

2. Could also be a clogged idle air passage, which is the passage that helps the computer set the idle speed...could be why it's idling low, if that's clogged, it can cause the shudder as well.
 
1. Check the vacuum lines, good chance that one of those is leaking or knock off messing with idle.

Off chance.

Check the plugs and wires also ... all it takes is a weak spark in a cylinder to throw things off.

Have an old timing light (useless for today's cars) that I use to check the wires on our Ford when it runs rough. Usually find a cylinder that isn't firing.

Though a bad battery could be just as bad, pulling the engine down enough to cause problems when something like an electric fan kicks on.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.