Thread: Rough idling

the IAC which i assume is connected to the speed sensor or simply is another name for the speed sensor,

The IAC is at the rear of teh plenum on the drivers side. You will see a big plug with 4? wires to it on the end of it.

The idle issues of 14CUX V8s are caused by a variety of factors-
High mileage so injectors drool
spark plugs old
spark plugs leads old
rotor old
dizzy cap old
valves worn and leaking
dirty throttle plate and body

I always found that in my RRC , the idle always deteriorated after say 30 seconds, and mine was perfect. The idle is better with aircon on as the mixture is more dense in the chambers so fires more easily. Also the stepper increases the idle speed to compensate for the load.

Mine now is much better with 4 hole injectors, but that is a bit extreme to fix a poor idle.

IMHO you should start by replacing the plugs, leads, dizzy cap and rotor. Rotor must be Lucas branded even if it does cost 5 times the cheap Bosch ones. And clean the throttle butterfly as the dirt reduces the air past the closed butterfly.
Regards Philip A

Originally Posted by PhilipA

The IAC is at the rear of teh plenum on the drivers side. You will see a big plug with 4? wires to it on the end of it.

The idle issues of 14CUX V8s are caused by a variety of factors-
High mileage so injectors drool
spark plugs old
spark plugs leads old
rotor old
dizzy cap old
valves worn and leaking
dirty throttle plate and body

I always found that in my RRC , the idle always deteriorated after say 30 seconds, and mine was perfect. The idle is better with aircon on as the mixture is more dense in the chambers so fires more easily. Also the stepper increases the idle speed to compensate for the load.

Mine now is much better with 4 hole injectors, but that is a bit extreme to fix a poor idle.

IMHO you should start by replacing the plugs, leads, dizzy cap and rotor. Rotor must be Lucas branded even if it does cost 5 times the cheap Bosch ones. And clean the throttle butterfly as the dirt reduces the air past the closed butterfly.
Regards Philip A

ok doing the leads and plugs tommorrow, will look up reccomentdations for leads and plugs, also engine has only done 50k km's so dont think it's high mileage, wish i read this this morning as i didnt check the IAC or TPS today ran out of time doing the sump gasket(rtv sealant) and gear box fluid, but tomorrow is another day to try eliminate rough idle, i will say i put in mutol 10-40w fully sunthetic(not sure whast was in there but was black and had quite a bit of gunk in sump) oil 70$ 5 litres and it honestly seems to have made a difference with overall running, and yeah spoke to my dad about injectors and he said is big move and uneccessary unless your are doing mods and tuning e.t.c, but will continue to post until resolved so newbies can work it out with som ehelp, which i had but alot of time people dont post once victorious which is the biggest benefit because alot of the time the problem can be identical or ruled out and move on to next one! stay tuned

I would start with checking of the TPS first ......

Mike