Mahoney,good choice.Go back with OE plugs and wires.Motorcraft,that is.

 

thanx this all helps even though mines a '99

 

my plugs and wires were just changed about 1000 miles ago. i thought that might solve my problem. i put ford plugs, and some $65 plug wires from auto zone on it. i had a local mechanic shop change the plugs, and now i'm wondering if they really changed the back plugs. they are so hard to reach, and i would never know if they got lazy and said screw it...

i don't know what else to do. i need that damn light to come, but it won't. i thinking o2, MAF, or fuel injector. the truck started the shaking very bad the past couple of days, but it only does it at maybe 1 in ever 20 stops... i might bite the bullet and drag it to the dealer. i have no idea how i would find a bad fuel injector.. any ideas?

 

plug, you may want to change the two o2 sensors just before the cat. convertors before you take it to a dealer. i do still have a rough idle but i have yet to expirience the REAL bad shaking since i changed the one out. it would be worth a shot and only cost $80 if you do it yourself. heck it would cost you that much just to have ford tell what they think is wrong with it (mind you what the THINK is wrong). i plan on changing the other o2 sensor this weekend and the plugs in about two weeks. will let you now if it helps my truck any........again try the o2 sensor change out i think it may help........good luck to you

 

mahoney22e,
the o2 sensor are about $40 a piece or are they $80 a piece? i know autozone sells the bosch 02 sensors for our trucks.

if i can get them both for around $80, i wouldn't mind trying it. my dad has a 4.6L also. so i could always put his MAF on my truck to be able to trouble shoot mine.

if the 02 sensors and MAF is not the problem, then i would think its a fuel injector. it could be coil packs, but i've tested them, and they seem fine; however, i read on here where someone had a bad coil pack that would only get out of spec when it was extremely hot.

 

plug,

yes you can replace two of them for $80. they have this special made socket that you can rent for $15 but when you return it you get it back. and i agree after all you have fixed,cleaned and tested if it is not the 02 sensor or maf then it probably it a injector issue. keep me posted

 

I would always change the air filter first. I found mine doing this when it gets a little dirty. All the rest of the good advice above should solve the issue.

tom

 

Just got my Lightning back from the shop for this very reason (rough idle, occasional stall) The diagnosis was dirty IAC and dirty injectors. So far so good.

 

dbmeriwether,

how did they diagnose the injector problem? and how much did it cost to have them cleaned? did you take it to a dealer to have the work done? i know it is not the iac in my truck because i put a new one in already....thanks

 

I just got thru reading a post in the V6 forum about some guys there having the same problems as you are.All of them were diagnosed as the Cam Position Sensor.Might be worth looking into.Good luck!

 

a mechanic freind of mine said the fuel injector cleaning would probably resolve the problem. i think its around $85 for the cleaning. he can't get me a deal cause it isn't his shop, but at least i know they won't be trying to screw me over with other fixes.

my iac is new also, i'm kind of in a bind over what to do. i might look into the cam sensor also...

keep me posted of any new updates, and i'll do the same.

 

I've got a '99 with the 4.6. It has done exactly the same as yours since it was new. It now has 85k miles and it's still the same.

If I turn the a/c off and run it on the highway, at high speeds, then get off into traffic. At the first couple of lights it shakes alot. It smoothes out eventually.

It almost never happens, or it's not as severe if I have the a/c on.

I took it to the dealer, who of course said "they can't reproduce the problem", because they weren't able to drive at high speeds for awhile. They also forgot to turn the a/c off.

Art

 

mine has always idled somewhat rough, but now when it goes into the bad idle at a red light or stop sign, the rpm's drop to about 400, and the truck acts as if it is going to die. mine does it with the ac on.

the ac will actually send a pulse to the pcm, to tell the computer to adjust the idle for the extra load of the ac. so the increase of fuel is probably what's causing your truck not to idle bad when the ac is on. have you tried replacing your plugs and wires? when plug wires break down, they usually start acting up when the heat of the engine is very high, and its usually the longest wires that go first.

also, check the pcv hose, you need to pull back the insulation right at the pcv valve, and check the the rubber elbow. once it wears, it will collaspe when it get hot. the rubber becomes weaker and the suction cause it to collaspe. its worth looking at.

 

Hi,
NEW TO THE SITE, BUT AM VERY INTERESTED. MY 98 F-150 4X4, FLAIRSIDE WITH THE 4.6L. NEVER GAVE ME A COMPLAINT TILL 60,000 MILES. STARTED PINGING UNDER HEAVY LOAD. RPM RANGE AROUND 3500. CHANGED PLUGS, PUT IN (50$) BOSCH PLATNIUM 2'S (MY SELF IN ABOUT FOUR HOURS) AT 61,000 MILES, CHECK ENGINE LIGHT CAME ON AT 63,000.

HAD DIAGNOSTIC DONE (FOULED #5 PLUG) OTHER SEVEN LOOKED BAD. HAD ALL REPLACED (TOO BUSY) WITH MOTOCRAFT DBL PLAT. CLEANED EJECTOR'S/FUEL SYSTEM/THROTTLE BODY($297.00) DROVE BACK TO WASHINGTON STATE FROM OREGON.

CHECK ENGINE LIGHT COMES ON AGAIN. LOOK UNDER HOOD MECHANIC LEFT VACCUM LINE FOR FUEL PRESSURE DIAPHRAM VALVE "OFF". DIAGNOSTIC SAID LOW FUEL PRESSURE, LEAN FUEL MIXTURE, MISS FIRE #4. (ALL MEMORY) CHANGE FUEL FILTER ($9.00) (JUST INCASE), CHANGE PLUG WIRES ($74.00) TURN OFF LIGHT ($10.00).

2 WEEKS LATER START TRIP BACK DOWN TO OREGON CHECK ENGINE LIGHT COMES BACK ON. BUT WORSE ALSO BLOW HEATER CORE. 2 DAYS OF RIPPING DASH BOARD APART(NOT DIFFICULT JUST SCARRY WITH HAYNES BOOK) A NEW CORE ($33.00) AND A COUPLE OF O RINGS (HEATER HOSES ARE QUICK DISCONNECT TYPE AT ENGINESIDE OF FIREWALL) AND I STILL HAVE THE OCCASIONAL ROUGH IDLE AND THE BLASTED CHECK ENGINE LIGHT. AT 65,000 MIL. AND A LOVELY COOLANT SMELL. BUT AS I TOLD MY CHEVY DRIVEING BROTHER INLAW. MY FORD HAS YET TO BE ANY-OTHER PLACE THAN INFRONT OF MY CAR TRAILER.

 

I had a problem with a rough idle on my 97 4.6 and I finally got a check engine light, it was my drivers side forward o2 sensor. Changed it and so far, about 3 weeks now, I haven't had a problem. Hope this helps!!!!