Lumpy Idle, TH 3.5

[Barry]

I have rough idle I can't get rid of too.

The values from my TPS seem on spec. 600mV at idle with a relatively smooth transition to 4.5 volts. Anyone think it might be worth replacing?

How much are you looking at for a new TPS?

IMO Don't spend all that money until you test the idle circuit.

At idle, the yellow/red wire is earthed by the TPS when properly adjusted.

It's switching a large voltage and eventually becomes ineffective.

Temporarily earth the yellow/red wire to the black and see if it improves after 5 Mins (don't rev engine at this time) An easy way to do this is use 2 pins to pierce the insulation on each wire and then join them, making sure they don't touch chassis. Use only these 2 wires ! If not experienced, get someone who is.

If still unsatisfactory, look to improving ignition/combustion

Cheers Barry

[Nexus]

Read all, it appears that this happens in nearly every 3rd gen and 2nd gen as well. My TE does the same.

To summarised what were the solutions:

Change Engine mounts
Use premium petrol
Use petrol cleaners
change spark plugs
clean the fuel system
Change to good grade Engine oil
Switch to N when at the traffic lights.

I do not feel confident that by changing engine mounts would solve my problem, how much does it cost to change them?

Why is it that it only happens when is at D and not N? and as soon as I drive the car, its smooth with no problems.

Like said its iratating sometimes and I would switch my Auto to N position which totally illeminates this rough idle. Changing Engine mounts seems to be the only thing I have not tried.

[FiveFourV8]

Hi all,

I started this thread orginally i dont know why my name dont come up!

Anyway beside the point, my idle was fixed for about 2 weeks by this magna freak i used to know in Sydney....He said he just cleaned all the gunk out of my throttle body.... and it idled perfectly for a week and a bit no joke..... and ive lost his number and i used to know his bro but hes going through a divorce... nto agood time to call.... i wish i could do what he did!!!!!!!! i was amazed

[FiveFourV8]

Have same problem in KH.

Replaces all plugs with irridium. No difference.
Replaces timing belt (was due). No difference.
Had throttle body stripped and cleaned (Little difference).
Engine mounts are Fine.

Mechanic showed me the air adjustment screw on throttle body. Just allows more air in at idle which in turn raises the idle manually. Doesnt solve the problem, just gets around it. This problem looks like it cant be solved anyway. Multiple mitsubishi mechanics say this makes absolutely no difference to performance/realiabillity of motor.

Have done it so car idles at 1000rpm at idle in Neutral and 900rmp in D (little higher than normal but gets rid of rough idle.) I am much happier now even though we have just gone round the problem and not solved it.

Can you tell me how to adjust the idle speed? I was thinking of doing this myself. Is it hard to do? thanks

[EZ Boy]

PCV valve- clean it.

Charcoal canister - check for leaks, cracks. Replace.