Help with rough idle
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,534
Likes: 7,638
From: MI
It sure does, a good sized one. A little rough, in need of fine tune (tweaking). Other than that. Yea, it's been cammed IMO. - Not too far from sounding GREAT!
Thread Starter
5 Year Member
Joined: Aug 2012
Posts: 2,310
Likes: 201
From: Albuquerque, NM
Happens on first start in cold weather bad enough to throw lean codes. And after its warmed up when I put it into park. Never while I'm driving unless the truck hasn't had a chance to warm up, even then it's minute when in gear.
While cruising on the highway I don't have any studdering/hesitation problems. At first I was thinking intake mani gaskets but I'm leaning towards a fuel pump on its way out now...
Not sure but when I get some extra cash it's going to the dealer for that and the left pulling problem.
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,534
Likes: 7,638
From: MI
Wish mine sounded like that lol.
Actually it did once as a matter of fact. Somehow I had a vacuum plug lodged in the IAC line. It probably rolled in there while on the bench.
Anyway, when low and loopy (idle) , I'd look for something plugged in the emission harness. Sometimes those little silicon 90* boots get shoved on there too far and totally blocks vac. There's a reveal on those 1/8" vac lines. The 90 can't be pushed past that or it WILL plug that section..it happens.
Idles reflecting a blockage IMO.
Or possible an EGR popet valve issue or malfunctioning solenoid within the same system = Green Line.
So go thru the emissions harness, also try disconnecting the green line from the EGR at idle, - see if that clears it up any.
Actually it did once as a matter of fact. Somehow I had a vacuum plug lodged in the IAC line. It probably rolled in there while on the bench.
Anyway, when low and loopy (idle) , I'd look for something plugged in the emission harness. Sometimes those little silicon 90* boots get shoved on there too far and totally blocks vac. There's a reveal on those 1/8" vac lines. The 90 can't be pushed past that or it WILL plug that section..it happens.
Idles reflecting a blockage IMO.
Or possible an EGR popet valve issue or malfunctioning solenoid within the same system = Green Line.
So go thru the emissions harness, also try disconnecting the green line from the EGR at idle, - see if that clears it up any.
Thread Starter
5 Year Member
Joined: Aug 2012
Posts: 2,310
Likes: 201
From: Albuquerque, NM
Wish mine sounded like that lol. Actually it did once as a matter of fact. Somehow I had a vacuum plug lodged in the IAC line. It probably rolled in there while on the bench. Anyway, when low and loopy (idle) , I'd look for something plugged in the emission harness. Sometimes those little silicon 90* boots get shoved on there too far and totally blocks vac. There's a reveal on those 1/8" vac lines. The 90 can't be pushed past that or it WILL plug that section..it happens. Idles reflecting a blockage IMO. Or possible an EGR popet valve issue or malfunctioning solenoid within the same system = Green Line. So go thru the emissions harness, also try disconnecting the green line from the EGR at idle, - see if that clears it up any.
Senior Member
Joined: Jun 2015
Posts: 288
Likes: 15
Use this site for the fix procedure. I did mine in a day. The hardest part is getting the bolts on the back of the intake along the firewall off.
https://sites.google.com/site/fordf1...P0171P0174-Fix
https://sites.google.com/site/fordf1...P0171P0174-Fix
Thread Starter
5 Year Member
Joined: Aug 2012
Posts: 2,310
Likes: 201
From: Albuquerque, NM
This was actually one of the first things I did. Bought new hose and pcv from the dealer.
Thread Starter
5 Year Member
Joined: Aug 2012
Posts: 2,310
Likes: 201
From: Albuquerque, NM
Use this site for the fix procedure. I did mine in a day. The hardest part is getting the bolts on the back of the intake along the firewall off. https://sites.google.com/site/fordf1...P0171P0174-Fix