Cleared all my codes but a new one popped up. P0507, and my idle was alright it would run low then jump between 1000-15000 “idle air control revolutions higher..”. So i ordered a cheap iac and replaced it assuming that was the deal and now when i start the car up it starts from 3k then when the car warms up it’s at 2000 then starts idling erratically jumping from 2000-2500. When i go into gear rpm’s go down to about 1000 but when coming to a stop the idling gets jumpy and erratic lower between 1000-1500. Car runs fine with the stock iac, just throws the check engine code. While the new iac left me with this crazy Idle and isn’t throwing me any codes whatsoever. Oem iac is on the way and no there are no vacuum leaks. I’m quintuple checking for vac leaks tomorrow.
P0507: Bad IAC?
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One of the vacuum hoses has white dashes and connects to the EGR Vacuum Control Valve...inside this hose is a restrictor valve that looks like a BB with a hole through it...this valve gets clogged, which disrupts the vacuum balance in the hose and messes with the idle. Feel along the white dashed hose to find the restrictor valve, remove it and clean it.. then reinstall it making sure the hole in the restrictor is properly aligned to allow flow. Basically, this restrictor is slightly narrowing the vacuum hose's inner diameter to compensate and balance the vacuum pressure. It would seem to be an afterthought design by Mitsubishi that is NOT well publicized, sort of like: "Hey, let's just put a restrictor valve in the vacuum line to solve the vacuum balance issue."
You can get the valve out by disconnecting both ends of the hose and push it out with a screwdriver, then push it back in after cleaning.
This may not solve your problem, but its a good idea to periodically clean the valve anyway, which I bet almost nobody does??!!
(do a search on this site for "restrictor valve" for threads on this topic, diagrams and pics included)
here's one: Restrictor vacuum hose (white painted hoses) p0401
You can get the valve out by disconnecting both ends of the hose and push it out with a screwdriver, then push it back in after cleaning.
This may not solve your problem, but its a good idea to periodically clean the valve anyway, which I bet almost nobody does??!!
(do a search on this site for "restrictor valve" for threads on this topic, diagrams and pics included)
here's one: Restrictor vacuum hose (white painted hoses) p0401
I also had this same problem. It turned out that one of the pin’s inside the plug itself was bent, which made contact with another pin... Probably not the problem you are having, but it’s worth checking just in case.
okay so here’s my problem today. No vacuum leaks. Nothing is clogged. I’m just wondering now, my MAF, IAC, and tps are all not OEM (replaced), if those are “faulty” or the computer won’t read them. Because when i let it sit and idle, i unplugged the new maf and boom idle is normal, plug it back and and back to erratic craziness 2k-2k rpm’s
Yes, it can be extremely frustrating when discovering that the "cheaper" non-oem part turns out to be a POS. There are certain parts for the 3g Eclipse that pretty much demand the use of OEM/stock/factory parts, and the MAF is definitely one of them. The OEM MAF for the Eclipse is unlike any other in design and function. There are threads here that explain why in detail, but suffice to say that it is a very sensitive and finicky design and that many if not most aftermarket MAFs just don't "communicate" well with the ECU. The OEM MAF is so intricate that cleaning it is NOT recommended...it is NOT serviceable!!!
However, inspecting and cleaning just the connector plug can sometimes help, so try that before returning the new MAF for refund.
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