Howdy, Im new here

I bought a '97 F-150 5.4L with ~96k miles (up to 99k now) and so far its been great except for one thing.

Sometimes (doesnt seem to be any rhyme or reason to it) it gets pretty rough when idling at a red light. I can feel it shaking pretty good.

Gas is somewhat high around here, so Ive been using 87, and Im wondering if I need to try 89? I suppose I could always try it for 1 tank and see what happens, although it seems like I can go a whole tank sometimes and thie problem wont occur, and sometimes it happens once or twice in one day.

My main concern is this: I had a friend with a '97, 4.2L, and his was idling rough as well. But his would sometimes get rough and then die on him. So far (?) mine has not died on me. He ended up having to get his engine replaced, something I really do not want to have to do.

Any suggestions? If you need more info just ask and Ill answer to the best of my ability.
Thanks.

 

Welcome to the board. A veritable $h*t-load of great information resides within these web walls.

I've got a '97 4WD 4.6L with a slightly rough idle...certainly nothing to worry about (I think). Your friend had to have the new engine?!?! What went wrong that it required a new engine? I'm curious to know what I should watch for so that I (we) don't have that problem.

Mine idles ~600-700 rpm and the idle doesn't drop, but just feels like it's occasionally missing. Can't remember what the idle was like prior to changing the plugs and wires tho. Just bugs me a little bit...like a rattle. But I'm rather **** retentive, so it bugs me alot.

Thanks...Scott

 

On mine, the RPMs dont change any, but the shake is pretty noticeable, I can look in the mirrors and see things shaking and you can feel it pretty well.

My friends truck: he said they took out the oil pan and found metal shavings...I changed my oil just recently but didnt notice anything like that (dont know if I would see problems like that just from removing the oil plug though?)

I forgot to mention, for my truck, when I first bought it the engine light did come for for the first few days, and I took it to AutoZone and the error codes said "right bank running lean" or something to that effect...but the light went away and I havent seen it since (that was ~a month ago).

 

A rough idle huh?

I"d start simple try some fuel injector cleaner and check your plugs they usually warn of any big trouble.

 

If it only happens once in a while at red lights it is prolly your IAC (Idle air control) they are well known to get stuck when they get old.

or:
new plugs
clean out throttle body (DO NOT USE CARB CLEANER!!! Use INTAKE cleaner)
clean MAF
run techron or Bg-44k through tank
replace fuel filter
lube throttle linkage
reset PCM

the 5.4 is famous for a slightly off/rough idle almost like a slight miss (which it isn't a miss) what you are describing is different.

good luck-

 

mine was doing that, and i replaced the iac valve and the rpms stoped dropping below 500 but it still does it but not as noticeable anymore. does the truck have an exaust system? my friend's truck shakes bec they got flowmasters put on their truck

 

check your iac valve and clean it. a lean code can mean a bad exaust sensor. there are a lot of threads covering this problem. just check thru the engines column.

 

I had all those things fixed on mine at the dealer. If it said right bank running lean, Change out O2 sensors on that side.

 

The truck is stock.

If the engine light stops coming on, is it possible that the problem is still occuring?

hcmq:
I'll see what I can do, my knowledge of engines and whatnot is pretty limited, but my dad may be able to help me out.

Thanks for the suggestions, Ill see what I can do.

Maybe this is just the "famous" rough idle, and Im just exaggerating/paranoid? Is there really any way to tell the difference?

Thanks guys.

 

had the same problem you are having with your rough idle in gear at a stoplight but not in neutral or park. i changed everything you could imagine (iac valve, cleaned t/b and maf, pcv valve, fuel cleaner, checked for vaccum leak) and nothing changed. finally i received a code and it was the bank 1 sensor1 the o2 senor just before the cat. convertor on passenger side. changed it and so far so good still a little rough but not nearly as bad as what it was.............................good luck

 

Mine does it in park and neutral as well :\

But, considering Ive got a CE light before, I should probably look at getting the sensor cleaned/replaced/whatever.

 

Mine has had a rough idle since 52k and has 56k now. Its a huntin' rig so gets driven every couple of weeks except when washed. we already put fuel inj. cleaner and changed plugs and wires. Any help please!!

 

Johngs,how is your coolant level? Go check out this website;
www.leakingfords.com

Johngs,after I posted this I realized you had the 5.4 engine.This website is for 4.2V6 engines.

 

I check it just about every time I check the oil (about once a week when I have nothing to do and it's fine.

Im gonna run it to Autozone today or tomorrow and have then get the codes off the computer, and write them down so I dont forget em

 

I have this same problem just starting with my 98 5.4. called the dealer and he says there is a coil over the spark plugs and it could likely be that.

Anyone heard of this?