juan5310

i have a 2003 Mitsubishi lancer es automatic
issues are as follows;

1.rough idle when stopped
2. car overheats when idle
3.gas mileage has gone really bad

i would type more but since i tried posting this earlier but for some reason logged me out and when logged back in the post was completely deleted ( 30 min of specifics) -_-

i also tried search but no related issues matched

hope some of you can help me address this issue.

RT78

Ok, as far as the rough idle, it could be a couple of things, dirty idle air control motor or a dirty egr valve. A failing map sensor will give you bad mileage plus a rough idle, the egr and iac you can clean, but sensors have to be replaced. However, never just assume anything is bad from symptoms, several parts have similar symptoms when they start to fail so if you just start replacing parts without knowing which one is the problem, the cost is gonna go up REAL quick. What really has my attention is the overheating, is your coolant level slowly dropping in the overflow tank at all?

juan5310

thanx for the reply, and actually the overflow tank is a little over the max (same as always) but a couple days i had put water in the radiator ( water bottle ) and hasnt overheated since but before that i did notice a little leak under the radiator.

as for other things i did replace the oil, oil filter and spark pluggs before all of this.

and someone i know who owns a car dealer did this thing where spray some type of thing through a tube that goes from the air filter to the engine and unplugged a cable or idk to this small little pressure tank i would say to " clean out the car engine " which caused white smoke to come out for a little bit but that was it.

how would i go cleaning those parts you mentioned ?

RT78

Well for the egr valve a how to video is here https://www.evolutionm.net/forums/lancer-how-tos-installations/694045-video-how-clean-replace-egr-valve-2002-mitsulishi-lancer.html and for the iac motor it's located here, be careful when taking the screws out, make sure you use the right size screwdriver because if they get stripped it's a pain to get em out. Use a wire brush to clean the pintle(tip) and the opening it goes into in the intake manifold.

RT78

I posted the location of the iac motor in this thread https://www.evolutionm.net/forums/la...-question.html Be careful when taking the screws out, make sure you use the right size screwdriver because if they get stripped it's a pain to get em out. Use a wire brush to clean the pintle(tip) and the opening it goes into in the intake manifold. And for that coolant leak, get that fixed when you can(sooner is always better). One thing you don't want to do is keep adding just water to the system, water has a lower boiling point than coolant and it could cause the radiator to crack when it boils. It's best to just keep adding coolant when it's needed. Another thing is you seem kind of new to auto repairs so I'd strongly suggest you start doing research on how things work if you want to start doing your own work, and if you know anybody who has hands on experience see if they can start to teach you as well. If you're not real familiar with stuff you can possibly do more harm than good, and things can get very expensive very quick.

Automatic 51

iTrader: (2)

What plugs did you use? Platinum plugs have caused issues for people in the past.

Rough idle could be anything from the egr valve, idle air controller to a vacuum leak or dirty maf. Unplugged maf or forgetting to plug the pcv hose back into the intake pipe can be causes as well. Do you have any check engine lights or error codes?

As for the overheating, low coolant can definitely cause that. Bubble in the system or bad thermostat also. If its an 03, the hoses or possibly the radiator with its plastic end tanks might be on its way out depending on where the leak is at.

Edit: the engine cleaning you asked about was likely Seafoam.

RT78

+1 on the plugs, I forgot about that. Typically it isn't the material of the electrodes (I have platinum NGK's in mine and it idles smooth as silk)as it is the manufacturer of plug and gapping. For Japanese imports the best plugs to use are either NGK, Denso, or Champion. Modern motors can be very sensitive to what kind of plug you use in them, I know from experience. I put Bosch plugs in my old GM and it idled horribly and I got pretty bad gas mileage. I switched them to ACDelco's and it purred like a kitten and mileage got much better. Gapping is also important as it determines how hard the ignition coils have to work to fire the plug, the bigger the gap the harder it is for the coil to bridge it.

juan5310

thanx for the replies you guys.

as for the EGR, i did clean it and it doesnt have a rough idle, and if it does its just a little bit......
but not as bad as before.

im starting to think maybe the ignition coils/spark plug wires, could be it ? maybe 1 or 2 ?

spark plugs are NGK iridium, soo it says lol

RT78

I'd try cleaning the iac motor as well first

juan5310

ok soo i took out the iac motor but had no idea how to clean lol so did some search and found this https://www.evolutionm.net/forums/ev...-idle-now.html

did as follows

"So I finally figured it out. After installing the IAC the idle screw was raised way high to compensate for the bad IAC originally. So the ECU wanted ~900 rpm but the car was set at 1800 to compensate for how screwed up the broken IAC was. After letting the car idle and warm up I reset the ECU so the SES light went off, restarted the car, and proceeded to adjust the idle screw back to 900. At first attempt it didn't work, I don't think I adjusted the idle screw close enough to what the ECu wanted, so I went for a run around the block, came back, let the car idle for a minute and shut it down. I reset the ECU by disconnecting the battery again, restarted, and once again the SES code was gone, so I adjusted the idle screw a little bit more until the car was idling again at a nice ~900 rpm. Haven't had an issue yet.

Like an idiot, I should have just played with the idle screw from the beginning until it was idling at ~900. Just for anyone that reads this in the future, the idle screw is on top of the throttle body, in a little hole. You'll need a shorty phillips/flathead screwdriver to reach it. Clockwise lowers the idle, counter-clockwise raises it. "

and my car idle normally after messing with it, but does a little tug once in a while, tommorow im going to put $10 gas ( its almost on empty) and see if maybe the gas millage changes which i doubt

02modlanceroz

iTrader: (2)

Did you put the car in SAS mode prior to adjusting the idle screw. If not, the IAC isn't properly set.

juan5310

how would i do that, i dont have a code reader thing available lol

marcouxa1

If you can log the datalist i would look at the engine coolant temperature sensor readings (ECT) if this sensor goes bad and reads a low temperature it will not activate your radiator cooling fans and will give you a bad idle.

juan5310

ok you guys soo i cleaned the throttle body with carb cleaner and the car idles smooth as hell now

but now im trying to figure out why the car accelerates weird, it does this normal acceration then a ( slow forced acceleration) and sometimes after, comes a hard kick ( sometimes) im not sure what to look up online, and today im going to check if gas millage is normal .

any ideas why it could be accelerating like this? maybe bad spark wires ? ima check transmission fluid

02modlanceroz

iTrader: (2)

I'm not really sure what you're trying to describe. Are the rpms erratic during acceleration or is it just shifting hard?