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2003 eclipse misfires and idles high


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zoggnoff
User

Jun 17, 2009, 10:09 PM

Post #1 of 5 (3575 views)
2003 eclipse misfires and idles high Sign In

2003
mitsubishi
eclipse gt
3.0L V6
140,000 miles

I bought an inexpensive scan tool that is throwing the code p0300.
I've replaced the IAC, PCV, throttle body gasket, radiator and changed the oil & filter.

I'm pretty sure the engine was misfiring before I replaced the IAC but it never idled this fast and is very random from 600-1000-1500 then back down again or sometimes not back down at all. the old IAC would stall when stopped and the AC was on. then one day it wouldn't idle at all... tested the ohms and they were near zero on one connector. bought a new one, mikuni brand.

also I think i have air in the brake lines which really makes me notice it at 1500 rpms... last time i did the brakes i didnt bleed the lines, just strong armed the piston back into place and by that i mean used a clamp :)

also i think the guy at the auto store gave me the wrong pcv valve, the picture on the computer was all black, the one that was in the car before was all black but the one they gave me is half white half black.

I have a vacuum gauge being shipped to me that im not sure where to plug in... intake manifold vacuum line? not sure where that is.

also it seems to be leaking oil.. i have checked under the car and it seems to be dropping out close to the alternator and not the plug nor the filter..
also i may have put too much oil in because recently there was some white smoke coming off the belt near the alternator.
threw water on the belt, let it cool... it stopped for a while then happened again but hasn't happened again since that day.

im thinking that the misfire could be plugs, wires, rotor, cap.
first i want to find if there is a vacuum leak though right?
and if i drain some of the oil , she might stop leaking oil? or is that a blown ring?
idle baffles me... could it be the wrong pcv valve? stuck open egr? is that cleanable?

ive got a scan tool, multimeter, haynes manual, internet, some borrowed sockets and soon that vacuum gauge.
and i have my eye on that actron pump/bleeder at sears

any advice would be appreciated.
thanks
mike


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 17, 2009, 11:14 PM

Post #2 of 5 (3568 views)
Re: 2003 eclipse misfires and idles high Sign In

The PO300 is a random misfire code. If the engine is due for ignition parts, then by all means, replace them first. As for the high idle problems, that generally means the engine is finding unmetered air from somewhere. Look around for any type of vacuum or air leaks that will contribute to that. You can use a can of carb cleaner to spray a little in any suspect areas to listen for engine change to indicate a leak.
See what you have after this and we will go from there.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Guest
Anonymous Poster

Jun 18, 2009, 1:22 PM

Post #3 of 5 (3558 views)
Re: 2003 eclipse misfires and idles high Sign In


In Reply To
The PO300 is a random misfire code. If the engine is due for ignition parts, then by all means, replace them first. As for the high idle problems, that generally means the engine is finding unmetered air from somewhere.


put the old PCV back on, p0300 code went away.

still have idle problem. idles 600 RPMs in (D)rive, shifting to (P)ark jumps 1300 then gradually descends to 1100, put in (D)rive back down to 600. I noticed jump in RPM is less when shifting to (P)ark on an incline, e.g. drive way. Also when I drive around in 30mph zones i let off the gas pedal and the RPMs seem to just stay at about 1000 and the car doesn't slow much unless i step on the brake then it will idle back to 600 and stay that way unless i hit the gas... im not sure if any of this is normal.

haven't looked for leaks yet


zoggnoff
User

Jun 19, 2009, 12:41 PM

Post #4 of 5 (3543 views)
Re: 2003 eclipse misfires and idles high Sign In

Okay, I used carb spray, found no leak.
friend suggested using soapy water.. used a gallon, still found no leak.
haven't received vacuum gauge yet.

I think my EGR is either stuck open or the EGR solenoid is broken.
I tapped on the TPS and moved around the wires to see if idle speed would change, it did not, so i think that is okay.
will test it with voltmeter tomorrow to be sure.
scan tool shows zero codes but also has 2 Incompletes - EVAP and EGR

The idle is rough and so is the exhaust

every once in a while I will be driving and the car feels like it shifts itself into neutral, the rpms jump, i left off on the gas it rights itself.
I think that may be an unrelated transmission problem though.

so what do you think?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 19, 2009, 10:19 PM

Post #5 of 5 (3532 views)
Re: 2003 eclipse misfires and idles high Sign In

I don't know where you got the soapy water idea but that will do nothing all for finding a vacuum leak. You use a combustable substance so the engine will react to inhaling it. If you suspect the EGR, then first pull the vacuum line off while it running, if that changes nothing, then remove the valve and examine it to see if the pintle is seated or not. If something is holding it open, then that was your problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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