Hi everybody, i'm brand new on here. I have an 03 ranger edge 4x4. Its got the 3.0 with the 5 speed. As far as modifications its got the superlift 4 inch lift with 33's. prerunner bumpers, k&n intake and flomaster exhaust. its go 118,000 miles on it. i've owned it since 06 and have never really had any major problems with it.

A couple weeks ago i noticed when i first start it, its idled a little rough, but once it got warmed up it would run fine. Also around this time it started idleing real high. i would pull up to a stop light and it would creep up to 3000 than go down to 2000 and back up again. Not too long after this my check engine light came on, so i took it to autozone to have it read and it said cylinder 4 misfire but nothing about the high idle. The guy told me it was probley the idle air control valve so i got one of those and also new plugs and wires. i first changed the idle valve and it changed nothing than i put the plugs and wires in and it than actually ran worse. someone else had mentioned that the idle isue could be the throttle position sensor so i pulled it off and cleaned it up and that actually fixed the idle isue. but it still runs like crap. so next logical thing i could think of was the coil so i got a brand new one and that didnt do anything. After this i took it back to have the check engine light read and now it said cylinder 1 misfire and also multiple cylinder misfires detected.

at this point i have no idea. its to the point where i can barely drive it because it runs so bad. its mainly between 1000 and 3000 rpm u can hear it missing the most. anybody got any ideas? fuel injectors? vacume leak? also has anybody had any bad experiences with the bosch platinum 4 plugs cause thats what it has in it. Although i had these in it before for probley the last 2 years and it ran great. I did have bosch wires and now i have the regular stock kind from advanced auto, could that be the issue?

I would say clean MAF sensor and then check for vacuum leaks

Spray some soapy water onto the vacuum lines while it is running.


Check this vacuum hose also even though you dont have the codes.

http://www.fordrangerforum.com/4-0-s...look-here.html

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ok ill try that

ok i cleaned the maf it wasnt too dirty but that definitly made it run better, still a little rough though and the check engine light is still on. ill check for vacume leaks again. would a vacume leak cause the check engine light to come on though?

well i just was listening to it run and i can hear a little tick coming from around cylinder 1. it sounds electrical. i pulled the plug and its just as white as when it was brand new just quite a bit of carbon around the outside. i pulled all the othe plugs and there the same just not so much carbon. im gonna go get some regulat plugs and see if that makes any difference. i have ran it for probley 50 miles with thes plugs in so the should be brown

First situation did sound like a vacuum leak. The rough idle and wondering rpms.

I think the original plugs should be re-installed to address the 'still runs like shit after the idle issue was resolved' thing.
The coils saturate and discharge at a certain controlled rate and no plugs but the direct replacement motorcraft/autolite seem to get the resistance value right. You can also check the spark gap. Plugs sometimes have more than one a pplication so they aren't always gapped for a certain motor.

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08 4.0 Sport 4x4
Stock

yup put the motorcraft plugs in and it runs perfect. i just dont understand why it ran fine with the bosch plugs in it for 2 years then i change them and it runs like shit. but anywho i got an almost brand new set of 6 bosh plugs for a ranger if anybody wants them, haha