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mike switzer
mike switzer,
Category: Australia Car
Satisfied Customers: 695
Experience:  lead diagnostic tech at Aamco
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I have just replaced my timing belt, water pump, sparkplugs,

Customer Question

hi I have just replaced my timing belt, water pump, sparkplugs, rocker gaskets and radiator on my Mitsubishi challenger 2002 6g72 3.0 lt and the vehicle ran fine at first for about 20 min I got back home shortly after went for another drive and the engine started to play up like it was missing and gradually got worse over the next hour or so, the next morning the car ran fine for 5 to 10 min got back home started the car again shortly after and it ran rough again I have pulled the front of the engine again to recheck the timing belt and it all lines up nicely still, I have unplugged what I believe to be the o2 sensor on the exhaust and no change can you help with this issue im supposed to be taking the family on holiday today so would like to get things sorted, Thanks
JA: Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: just rechecking timing and the 02 sensor it seems to be running rich as I can smell unburnt fuel
JA: Is there anything else important you think the Mitsubishi Mechanic should know about your Mitsubishi?
Customer: no
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Mitsubishi Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Australia Car
Expert:  mike switzer replied 1 year ago.

hi are there any codes in the system or is the check engine light on?

Customer: replied 1 year ago.
engine light is not on, I believe a light flashes for engine codes I cant remember, I did disconnect battery positive for several minutes as I have read this will clear any codes that come up.
Expert:  mike switzer replied 1 year ago.

if the engine light is flashing that signifies a catalyst damaging misfire. it sounds to me like you are having a misfire when the vehicle warms up.

Expert:  mike switzer replied 1 year ago.

do you have easy access to al the spark plug wires?

Customer: replied 1 year ago.
I have access to the wires at the coil end the other end at the plugs is covered by the intake manifold
Expert:  mike switzer replied 1 year ago.

then my idea i wouldnt recommend.... is the crank sensor located behind the timing cover down by the crank pulley?

Customer: replied 1 year ago.
Expert:  mike switzer replied 1 year ago.

if you have access to that i would try changing that first to see if it goes away.

Customer: replied 1 year ago.
sorry to be clear you recommend I change my crank sensor, I am unsure as you said I wouldn't recommend
Expert:  mike switzer replied 1 year ago.

i am sorry yes that is what i ment i would try replacing the sensor first.

Customer: replied 1 year ago.
ok thanks I will look into that first
Expert:  mike switzer replied 1 year ago.

ok please let me know what happens and if you may give me a rating.

Customer: replied 1 year ago.
Hi mike, I have tested both the cam shaft and crank shaft angle sensors electrically, both are receiving 12v and are returning 5v (as is normal) on the return blue wire and returning 0v when metal is not within the sensor so both are working correctly.
Expert:  mike switzer replied 1 year ago.

have you tested them while the vehicle is messing up. im thinking that the engine heat may be disrupting the signal.

Expert:  mike switzer replied 1 year ago.

although if they still test out okay i would check your ignition system. the three coils infront can be unplugged one at a time while the engine is running rough to isolate the issue to what cylinder. although one coil runs two cylinders i dont recommend unplugging the wires one by one as you will most likely shock yourself and it does not feel good.

other than the ignition system it could be a fuel issue but is unlikely.

you said you rechecked your timing alignment and so i am not looking at that for now. and considering the symptoms i dont believe that could be an issue.