2003 Idle - missing - I give up

[David Schmidt]

I've been trying to get my 2003 V6 to run smooth for 2 years now. 92,000 miles. Symptoms are it burps or misses often. The burp sound is the sound you get with the K & N intake it. It burps at idle every once in a while but its when it gets a load I get a miss. All conditions. Change from Park to Drive or Drive to Park - "burp". Turn steering wheel all the way to put load on pump "bump". Lights come on and alternator gets a load "burp". Press the gas and "burp". Biggest annoyance every time the a/c engages or disengages "burp". Any type of engine load. I give up..



IAC replaced 10K ago. New iridium spark plugs at 60K. New wires and Screaming Demon coil installed. New factory EGR valve installed. Two new upstream Oxygen sensors installed. Removed throttle body and super cleaned everything. Cracked elbow replaced head to toe and new pcv valve installed. New fuel filter installed. Sea Foamed a couple of times. Not sure what I'm dealing with - electrical issue, vacuum issue, valve issue, fuel issue. The truck gets GREAT gas mileage at 17.9-18.3 mpg, hauls butt, starts up instantly, goes great down the road. I do notice if I manually hit the throttle to like 1500 rpm or whatever and the a/c clutch engages / disengages I can still feel the "burp" a bit so its not just at idle but thats the only time you can hear and feel it when driving. What did I leave out?

 

[David Schmidt]

oh yeah...no codes...no pending codes are present either. Just runs like crap.

 

[user 66225]

I've heard that the OEM Motorcraft spark plugs are recommended, in lieu of the "fancy" aftermarket ones...

 

[shawn stonbraker 2]

I also have a 2003, and have had the same symptoms you are describing during idle from day one. It has never idled "smooth". Now during driving conditions, it runs nice and smooth, just during idle (in park or at a stop light) there is what I call a "hick-up".



I'm wondering if maybe you have a bad MAF sensor. Not bad enough to give a code, but may have some oil on there from the K&N filter. I did notice my "hick-up" lightening up after I bought an Oiless Cone Filter off Todd. Took off the oiled cone and cleaned the entire intake including the MAF and put the oiless one on.



On a side note, I learned first hand about off brand (not OEM) spark plugs and the Ford 4.0 engine. Thay don't play nice together. What brand was in there before you put the Iridiums in?

 

[Les]

I would change the plugs to original Ford and reinstall the original coil pack if you have it.

 

[EddieS'04]

If you have the stock coil. Put it back on and see what happens. We have had a rash of members with bad SD coils. Unless it was doing it before with stock coil.



Also if it wasnt doing it before the new plugs. You may have cracked a new one on install. Easy to do, especialy pasenger side. Might be a bad wire. It happens even with new ones. If you have a vom. Run a resitance test on the plug wires. If they are oem type wires. The resitance will be aprox 1500 ohms per foot. Custom performance wires, aprox 500 ohms per foot.



As others said. Some members had bad success with custom plugs. The 4L sohc runs as good as it gets with motor craft or autolite oem.



Also check all conections from the harness to all critical sensors. A little loose or corrosion can cause trouble and not set off code. Clean the maf with crc maf cleaner from AZ.

 

[Todd Z]

Did you try unplugging the AC compressor and trying that ???



Double check all plug connections ??



Switch out the SD coil and put the OEM one back in ??



Todd Z

 

[David Schmidt]

all good suggestions - I'm hesitant on a few items because the "hick up" or "burp" as I call it was before and after the plugs and new coil. New plugs are fairly cheap - I have my old ones still so I will get the exact original model which is AGSF-22F-M (SP-500). But yes - my next step is to play around and put stuff back on. I keep the MAF sensor clean with MAF cleaner and clean regularly because of intake. Throttle body is super clean. I didn't unplug a/c compressor - I don't think its the issue as power steering pump, alternator, transmission- ANY type of momentary strain on the engine causes a "miss" or "burp" - "hiccup" is a better word I guess. Runs great though. I do have my original coil - the hiccup was before and after also. I think I'm gonna start with the spark plugs - I have 30K on iridiums so they weren't a complete waste of money. Then coil I guess. I've looked at just about every connection I could think of - cleaned - diaelectric grease - put back on - all in good shape.

thanks - I need some more motivation..its falling apart these days.



Other annoyances fixed:

Both rear head rests self imploded themselves. They never get used - gotta be design issue. I super glued and filled them with foam - fixed for now. I had the famous front end squeak - greased up sway bar fittings - problem fixed. My favorite - had a very loud suspension clunk for 2 years or so. Thought all the ball joints were shot. My brother said get me a 21MM deep socket at xmas - ok - he tightened both the upper control arm nuts on both sides - clunk gone - 2 minute fix without even taking a tire off (all ball joints good) - 2 years of every bump sounding like the end of the world. Of course I did the better rear swap bar, new shocks, michelins to fix the FORD defect of tire cupping they refused to fix - no problem since but drove with a thumping sound for over a year. Cracked PCV hose of course - all new now. Now last week I'm getting the "CD Error" and all six disks are stuck inside. At least I have a new hobby now. Time for a beer.

 

[EddieS'04]

Could be the IAC is not reacting quik enough to needed idle change. Try tweaking the throttle plate set srcrew 1/4 turn open. Do this with motor cold. Disconect neg battery cable 10 minutes. Start motor let idle till operating temp. To relearn idle.