Rough idle
Thread Starter
|
Member
Joined: Sep 2018
Posts: 1
Likes: 0
From: NY
Rough idle
I have a 2001 4.0 v6, Friday after work I started my truck and heard a loud bang, saw smoke rolling out from under the hood and then began to investigate, I noticed a PCV line was blown off one of the boots and so I put it back into the boot and hose clamped it. Later on I saw that my truck threw the P0300 code for multiple cylinder misfire. Turns out I had a lose spark plug on cylinder 4. I had tightened that plug up as well as the rest and the code went away. My truck now idles fine except for when I rev it up it spits and sputters when it revs up and idles back down and sounds like it’s misfiring , and there is a strong aroma of fuel , any ideas I’m stumped. Fuel rail pressure problems? Fuel filter? Fuel pump? Clean IAC and MAF? Please help me out as I am using s company vehicle until I can get this figured out. Thanks.
Welcome to the forum
Reads like you had a back fire into the intake manifold, that would explain the PCV hose coming off, and some smoke coming out of it, this is a vacuum hose so shouldn't need a clamp, connections are "pulled" together by vacuum(lower pressure) inside the hoses and connections, not "pushed" apart like other hose connections that have higher pressure inside.
But clamping it is fine
You have a 4.0l SOHC engine, 2001 to 2012 Rangers
These did have a problem with PCV hoses cracking at the elbows so check for that, it causes a vacuum leak and misfires
So first thing I would check is the PCV hose, from intake to PCV Valve, check under the elbow, that where it would crack
Pictures here: https://www.ranger-forums.com/4-0l-o...mon-cel-93776/
There is a simple test for a vacuum leak
Warm up engine first and let it idle
Locate IAC(idle air control) Valve on upper intake, it has a 2 wire connector
Unplug this connector
IAC Valve will close and engine RPMs should drop down to 500 or so, engine may even stall, either is good, if means no vacuum leaks
If RPMs do not drop then there are leaks
Reads like you had a back fire into the intake manifold, that would explain the PCV hose coming off, and some smoke coming out of it, this is a vacuum hose so shouldn't need a clamp, connections are "pulled" together by vacuum(lower pressure) inside the hoses and connections, not "pushed" apart like other hose connections that have higher pressure inside.
But clamping it is fine
You have a 4.0l SOHC engine, 2001 to 2012 Rangers
These did have a problem with PCV hoses cracking at the elbows so check for that, it causes a vacuum leak and misfires
So first thing I would check is the PCV hose, from intake to PCV Valve, check under the elbow, that where it would crack
Pictures here: https://www.ranger-forums.com/4-0l-o...mon-cel-93776/
There is a simple test for a vacuum leak
Warm up engine first and let it idle
Locate IAC(idle air control) Valve on upper intake, it has a 2 wire connector
Unplug this connector
IAC Valve will close and engine RPMs should drop down to 500 or so, engine may even stall, either is good, if means no vacuum leaks
If RPMs do not drop then there are leaks
Last edited by RonD; Sep 20, 2018 at 11:14 AM.
Thread
Thread Starter
Forum
Replies
Last Post
IronHorseDriver
4.0L OHV & SOHC V6 Tech
1
Feb 6, 2016 05:44 PM
