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2003 Ford Explorer 4.0 V6

bdelapp

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Year, Model & Trim Level
2003 Ford Explorer
Have spent around $1,500 chasing a problem:

At start up cold idle is rough, scale of 1/10 is a 4.

As proceed down street before engine warms up it surges and records a P302 code.

Once engine warms up it runs fine.

Last August MAJOR (all OE parts) tune up, i.e plugs, coil, wires, fuel filter, air filter, complete diagnostics all performed by master mechanic at highly reliable local licensed shop.

You name it, it was replaced, including a complete 'induction service'.

Still rough idle while cold and 1 surge / dead miss before warming with one code: P302.

This year component tested and replaced #2 injector, cleaned and scoped
intake, ran complete diagnostics rechecking everything replaced August 2014, PLUS leak down, compression, fuel pump pressure and far too much to mention.

Still has rough idle when engine cold and one surge / miss on #2 causing idiot light to flash and stay on yet once engine warms up it seems to run fine.

In researching on the internet it appears this is a very common problem with the 4.0 SOHC V6 yet no general consensus of what fixes it.

Suggestions? :(
 



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Hi

Thanks for your input and I'll check with the mechanic but I assume he put a new O-ring when he replaced the injector? :)

Yes, the mechanic tested for and physically checked for vacuum leaks.
 












Thanks Gilbert

Welcome from Costa Mesa, California!
:usa:

HELP1!!!!!!

I'm still chasing my problem (see my original post) with no luck.

As a bit of info, I grew up working on my car(s) and as a mechanic in a Shell station. Modestly, I WAS a damn good mechanic before all the electronics.

Not being a novice, I believe every possible test has been ran to date on the vehicle and my mechanic is scratching his head and we still have no answer.

The idiot light is constantly on and occasionally flashing, there is clearly a miss which seems to have become the norm at cold idle and until the engine reaches operating temperature, a minor pfft pfft exiting thru the exhaust along with a raw gas smell, and as apparently is a NORMAL problem, given the info discovered on the internet with this 4.0 SOHC V6 the dreaded P302 code.

Any help / suggestions greatly appreciated as I must have the vehicle emission tested before I can purchase our 2016 license at the end of February this year.

:confused:
 






Welcome to EF. Are you using any coolant?.
 






Welcome to EF. Are you using any coolant?.

To the coolant question Mike... yes, the plastic thermostat block leaked last year and when my mechanic replaced it they added a standard coolant in the recommended amount.

:)
 






To the coolant question Mike... yes, the plastic thermostat block leaked last year and when my mechanic replaced it they added a standard coolant in the recommended amount.

:)

Have you used any coolant since?
 






Coolant

Have you used any coolant since?

I top off the overflow tank in the vehicle about once a year.

Compression and over night leak down test both passed.

I'll throw this in the mix.

2003 Ford Explorer

4.0L SOHC V6-245

June 2014

Car began to idle rough when cold and seemed to improve upon reaching operating temperature. Within a week, the idiot light came on and began to flash at various times.

28 July 2014

I took the vehicle to a local and highly recommended garage for inspection. The mechanic performed an ECM scan and suggested a complete tune-up as the vehicle still had the original plugs and ignition system at more than 108k miles.

August 22, 2014

I returned to the garage for other work and ordered an estimate for a complete tune-up.

The mechanic performed a full ignition tune-up – OEM wires – coil – Suppressor spark plugs – induction cleaning service – fuel filter – air filter.

NOTE: Before I arrived home, (approximately 4 miles) the engine was again idling rough and the idiot light flashing. I returned to the mechanic who suggested a ‘possible fuel’ injector problem and that I fill up with premium two or three times to see if idle improved and if not bring it back.

As an FYI here: we are retired, drive the car very, very little so it was a year later when we finally returned as instructed.

3 September 2015

I took car back to have the AC repaired and I revisited the rough idle and P302 miss problem with the mechanic and he volunteered to retest.

He performed a complete retesting of the engine and there was the dreaded P302 code.

I say “DREADED” as from my online research it appears the P302 code in particular is a BIG PROBLEM with this engine. Worse yet, there are at least a dozen different methods of repair listed for this problem alone.

I ordered him to replace the injector.

Afterwards, the mechanic road tested the vehicle and it still had a rough idle, idiot light on and a P302 code.

He voluntarily (no charge) ran numerous additional tests, i.e. compression, vacuum, retested coil, wires and plugs installed the past year, performed an over night air pressure test on the #2 cylinder and several other procedures too numerous to mention.

January 2016 – the explorer still the same: rough idle, idiot light constantly on with occasional flashing (15 count), a raw fuel smell when sitting still and a minor pfft pfft from the exhaust.

At the end of February 2016 I must have an emission inspection, which it will not pass with the idiot light flashing and the raw gas smell.
 






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