2001 F150
Thread Starter
|
4th Gear
Joined: Mar 2024
Posts: 4
Likes: 0
2001 F150
Hello I’m new here. My name is Jason.
I could really use some help. My 2001 F150 has a v6 4.2, it is running really rough. I’ve replaced plugs,coil,plug wires,fuel filter and gutted the cats. Still has a what I’m calling a miss. Not real bad at idle in park but when I put it in gear it’s bad. Any help would greatly be appreciated. Thanks
I could really use some help. My 2001 F150 has a v6 4.2, it is running really rough. I’ve replaced plugs,coil,plug wires,fuel filter and gutted the cats. Still has a what I’m calling a miss. Not real bad at idle in park but when I put it in gear it’s bad. Any help would greatly be appreciated. Thanks
Fleet Mechanic
Joined: Jul 2019
Posts: 1,317
Likes: 313
How many miles on the engine?
What did the spark plugs indicate?
Why are the cats gutted? That’s not a repair.
You may indeed have a miss. Time to pull a compression test.
Contrary to popular belief, 20+ year old engines tend to be passed their best life and some heavy work may be in store.
What did the spark plugs indicate?
Why are the cats gutted? That’s not a repair.
You may indeed have a miss. Time to pull a compression test.
Contrary to popular belief, 20+ year old engines tend to be passed their best life and some heavy work may be in store.
5th Wheeling
Joined: Jan 2024
Posts: 49
Likes: 5
From: FL
I agree about isolator bolts. Don't rule out bad air plenum manifold (aka intake manifold upper/lower clamshells).
An easy check is to pull off vacuum line from brake booster to check with a vacuum gauge. After that, reconnect vacuum line.
Later you could pull off all six plugs, use compression tester and write down compression for each cylinder. As a reference, my 2001 F150 4.2 runs 20 in/Hg at idle (with new air plenum manifold and sealing gaskets).
All my engine cylinders run at 190-200 psi. It purrs like a kitten, and mileage is +170k as of date of this post.
An easy check is to pull off vacuum line from brake booster to check with a vacuum gauge. After that, reconnect vacuum line.
Later you could pull off all six plugs, use compression tester and write down compression for each cylinder. As a reference, my 2001 F150 4.2 runs 20 in/Hg at idle (with new air plenum manifold and sealing gaskets).
All my engine cylinders run at 190-200 psi. It purrs like a kitten, and mileage is +170k as of date of this post.
Thread Starter
|
4th Gear
Joined: Mar 2024
Posts: 4
Likes: 0
Thanks
Thanks to all for input. By the way truck has 198,000 miles. It was my father in law’s truck and he gave it to me before he passed whenever he wasn’t able to drive anymore. The truck means a lot to me so I’m determined to keep it going. I will do the intake this week and report back. Do I need a new intake or just gasket set? Thanks again
5th Wheeling
Joined: Jan 2024
Posts: 49
Likes: 5
From: FL
A compression check will establish a road map of where to proceed with the engine problem(s). 198k isn't a bad number for vehicle if the bottom end is good. As I stated in previous, my 2001 F150 4.2l has 170k miles and it's still got a lot of life on the engine.
You need a mandatory compression test to get a start on things like valves/cylinder heads condition, possible timing/camshaft issues, some of which will also affect vacuum in the plenum manifold on top of the motor. You'll probably need a tester with the Lisle 20280 adapter since the plugs sit way down in the manifold and a normal compression tester hose won't screw all the way in to get a compression reading.
You need a mandatory compression test to get a start on things like valves/cylinder heads condition, possible timing/camshaft issues, some of which will also affect vacuum in the plenum manifold on top of the motor. You'll probably need a tester with the Lisle 20280 adapter since the plugs sit way down in the manifold and a normal compression tester hose won't screw all the way in to get a compression reading.
Trending Topics
Fleet Mechanic
Joined: Jun 2023
Posts: 1,379
Likes: 383
From: WA
You should do more diagnostic work before replacing any parts. People are assuming that you need isolater bolts and manifold gaskets (no offense intended to those people). Both of those problems will show up in live data using a simple cheap OBDII scanner. Besides that, the PCM will compensate for intake leaks by adding more fuel, and there will be no miss, it will run fine.
It might be too late but how did the old spark plugs look? Each used plug has information about how that cylinder was performing.
And, another reason to get a cheap scanner and use it is because, since you gutted the cats, you'll have a permanent check engine light and will not be able to tell when things are right. Best to learn how the system works and do some proper diagnostics first, before replacing parts.
It might be too late but how did the old spark plugs look? Each used plug has information about how that cylinder was performing.
And, another reason to get a cheap scanner and use it is because, since you gutted the cats, you'll have a permanent check engine light and will not be able to tell when things are right. Best to learn how the system works and do some proper diagnostics first, before replacing parts.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Hotshot
Joined: Jul 2020
Posts: 10,519
Likes: 2,654
From: Near Salt Lake City
I did not need a new manifold on my 04 with 174k 4.2l
I did need new injectors and isolator bolts upper and lower plenum gaskets
Double check the EGR ports on the lower manifold while you have the upper off
Your 01 has a different style of dual intake runner control
Verify all of that works and the flaps are not broken when it is off
Yours is vacuum operated and there will be codes for that system if it malfunctions hopefully
Enjoy your inherited truck
Take good care of it and it'll take good care of you
Use all Ford parts fixing it with the exception of gaskets and isolator bolts like right now
Might need to go aftermarket for the manifold if you need one
Look for witness marks where the gasket was either sealing or not sealing, and smoke test it before you replace the manifold
Buy a cheap scan tool online
Check the codes once in a while
Deal with the lowest numerical code first
I did need new injectors and isolator bolts upper and lower plenum gaskets
Double check the EGR ports on the lower manifold while you have the upper off
Your 01 has a different style of dual intake runner control
Verify all of that works and the flaps are not broken when it is off
Yours is vacuum operated and there will be codes for that system if it malfunctions hopefully
Enjoy your inherited truck
Take good care of it and it'll take good care of you
Use all Ford parts fixing it with the exception of gaskets and isolator bolts like right now
Might need to go aftermarket for the manifold if you need one
Look for witness marks where the gasket was either sealing or not sealing, and smoke test it before you replace the manifold
Buy a cheap scan tool online
Check the codes once in a while
Deal with the lowest numerical code first
Thread Starter
|
4th Gear
Joined: Mar 2024
Posts: 4
Likes: 0
Misfire on 2 and 5
I pulled codes and shows to have misfire on 2&5. I swapped the coil out with a used one that I know was good and it didn’t change. Also checked compression on all cylinders and they range from 148-152
Fleet Mechanic
Joined: Jun 2023
Posts: 1,379
Likes: 383
From: WA
Did you "pull codes" at the auto parts store or do you have a tool? Live data will tell you a ton about what's happening if your scanner does it. If your fuel trims are good, that's a sign, if they're off, that's a sign.
More Turbo
Joined: Sep 2017
Posts: 574
Likes: 146
Thread
Thread Starter
Forum
Replies
Last Post
erik001
1987 - 1996 F150 & Larger F-Series Trucks
1
May 14, 2012 11:07 PM