hey i need help my 2011 ford ranger 4.0 with over 119,000 miles has 4 codes for multiple cylinder misfire detected it also has codes cylinders #1,2,& 3 the plugs & wires are not that old the last 30,000 miles its been running rough for a while now i've replaced the MAFS, IAC, i recently changed the oil and it had a strong gas smell also i've notice a strong gas smell out the exhaust the last few weeks i've been told it's more then likely the coil pack has gone bad since it is the original gonna to change the coil pack hopefully that will fix it does anyone have any experience with this engine this engine has some of the most ridiculous issues ive ever seeing

 

What Brand+Model Plugs+Wires did you install?
Consider also changing OxygenSensors +FuelFilter, they wear out, needed every 100kMiles\12yrs, along with Plugs+Wires.
Has ThrottleBody +IntakeManifold +IACValve +EGRValve +PCVValve been cleaned\renewed recently?
New\clean AirFilter? With weather cooling off, any rodents in AirFilter box?

 

All except o2 sensors have been replaced with oem parts

 

Gas smell from exhaust may be indication that OxygenSensors are worn out & biasing Fuel/AirRatio to the rich side;
makes CatCons run too hot & lowers gas mileage.
Certainly could also simply have a fuel leak.

 

im gonna replace the coil in the morning if that doesn't fix it then i will replace the O2 sensors the check engine light isn't showing O2 sensor fault i'm almost sure the biggest problem is the coil is wore out but the O2 sensor could be bad as well

 

1, 2 and 3 misfire is one whole Bank of the overhead cam V6 engine........................so I would do a compression test on #1 and then #4 or #5 to make sure the Cam on Bank 1(passenger side) hasn't slipped
Expected pressure is 165-175psi, but over 150psi on both sides would be OK if all spark plugs are not removed

The coil pack only has 3 coils inside
Each coil sparks 2 spark plugs at a time
1/5
2/6
3/4
Are the 3 coil pairs
If 1 coil in the pack fails then one pair will misfire, i.e. 1 and 5 misfire codes
1, 2, and 3 codes means all 3 coils failed and engine couldn't run at all

Only other thing, besides the Cam slip, to cause one Bank to misfire would be a blocked exhaust just on that one bank, i.e. if it has a Cat converter on that one down pipe maybe its collapsed
If you pull out the O2 sensor on that side to give exhaust another exit and it runs smoother then that could be the reason for the codes, it WILL BE LOUD, lol

The 4.0l SOHC engines do not use woodruff keys to hold cam timing, they use "friction fit", the gear and shaft are tapered so when tightened the "friction" holds the timing, on paper, lol
So it is possible for one bank to go "out of time" which lowers the compression on that bank and causes the misfires

 

i had the ford dealership look at it they said the timing chain tensioners need to be replaced they think that's causing it to misfire i have a feeling its the crankshaft positioning sensor again but will find out after they replace the tensioners they were replaced 30,000 miles ago

 

So I got a call from the shop the engine jumped time again they said the back guid is broken this time last time it was the front i have a feeling the guy who replced the timing chain didn't replace both guids they are recommended replacing the engine due to the mileage it has 119,000 miles i have them getting me a quote to replace the guids does anyone have any suggestions on what I should do the cost of a rebuilt engine is over $5000.00

 

The Guides or the chains were never an issue in the 4.0l SOHC engines
The 2 long chain tensioners were the issue from day 1 in 1997 when this engine was first put into Explorers
Not a 100% failure either, maybe 25% failure rate, which is way too high, but not 100%

Took until 2000/2001 for Ford to figure out that the springs in the tensioners were failing, this allowed the chains to beat on the guides on startup, because there is no oil pressure when cranking engine over, oil pressure holds tensioners tight once engine is running, but eventually a guide would break on start up, and then you have the "death rattle", damage done, no previous warning for this

Ford redesigned the tensioners and the new design was in 2004 and up Rangers but the tensioners should be changed every 100k miles regardless

Broken tensioner or broken guide wouldn't cause it to skip time, just "rattle"

The 4.0l SOHC doesn't use keyways to hold time, like most engines now-a-days, it uses "friction fit" to hold timing gears on cam shafts, tapered gear and shaft then torqued down to hold time, and they use TTY bolts in most cases, which means they shouldn't be reused, but often are without bad results, but.....................


If they warranty the engine then the $5,000 isn't that bad for 0 miles starting point