Engine Shaking w/ low idle

[whiteturboz89]

hello, after my engine is warmed up the idle becomes very low and it goes up and down between 500 and 1000 rpm. i've asked my friend, and he told me its exhaust leak back fire. im not sure if hes right

im really new to cars in general, any advice would be great thx.

 

[Mischief7m]

sounds to me like if its an unsteady idle, it could be your idle air control valve, butt there isnt really enough info to tell. check your codes..

 

[johnathan1]

Do this: http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

And then report back here with your findings.

 

[plaaya69]

I just fixed my very bad exhaust manifold gasket and turbo exhaust leak but that did not give me a bad engine shaking. I would check for codes, inspect the ISC, inspect the intercooler pipe clamps and make sure their is no cracks, and how are your spark plugs/wires/coil packs(if turbo)?

 

[whiteturboz89]

wow u guys, thx for the fast repleys u guys gave me alot of things to ask my mechanic about.

im currently in my uncles shop right now, gonna check the ecu codes.

i cant find the EFI fuse (15A. where is it?

 

[ValgeKotkas]

Engine bay fuse box?

 

[whiteturboz89]

i just put the paper clip in tem1 and e1, and turned on the engine. how come i dont see the engine check light blinking? it showed once when i turn the motor on and it disappeared

 

[cuel]

You don't have to start the car. You can check the codes with the key in the "On" position.

The c.e.l. should be on constant with the key on(engine off), no jumper. When you put the jumper in Te1 and E1, the light should start flashing. It will either flash steadily, or a code. If the c.e.l. isn't lighting, then you need to check the fuses, or the bulb shorted out. I'm not sure what fuse the c.e.l. light is on. I would guess cig., but I could be wrong...

This is the fuse box under the hood, where the 15a efi fuse is: http://cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=18

 

[ForcedTorque]

No blinking either signifies no codes, or that you haven't done it correctly. Also, if you just cleared the codes with the EFI fuse before hand, you will want to run the car a while before checking codes, because they are now gone.

You could also have a boost leak somewhere between the AFM and the throttle body. The small coupler between the 3000 pipe and the Throttle body is a weak link, as well as the small hose coming off of the throttle body to one of the tubes that crosses the motor behind the 3000 pipe. This is all assuming a turbo car though.

Just today I corrected a leak at my throttle body, and smoothed my idle quite a bit.

Also....If you just bought the car, your check engine light may be disconnected for selling purposes.