The other day my 2002 Sport Trac with 4.0 started to miss badly. It has only about 90,000 miles on it. It started to do this suddenly from one turn of the key to the next. It also makes a weird noice that sounds as if its coming from the intake area that can be described as a "chuffing" sound thats in time with the engine. The intake also gets very warm to the touch. We have since stopped driving it. I sprayed carb cleaner all around where the intake meets the head with no change in rpm. I also checked the plastic hose that goes behind the engine to the pcv valve and its ok.

Does anyone have any ideas what it may be before I take it in the shop?

Thanks to all,
Nitro

 

When it's making this noise and misfire, what is the engine speed? If quite low, what happens if you increase the engine speed to around 650 rpm? If the engine smooths out at around 650 rpms, the noise you are hearing, source of heat, and issue with the "engine" may be as simple as a faulty Idle Air Control (IAC) servo.

-Rod

 

Thanks for the quick reply Rod. It starts making this noise soon as it starts up. The noise and miss continue as rpm's increase. It sounds and runs as if a sparkplug would be removed and the hole left open but not as severe as that example.

I forgot to mention that the check engine light is on.

'Nitro

 

I would check several possibilities.

• The EGR may be sticking partial open, allowing exhaust gasses into the intake at low RPM...
• You have an intake valve that has lost its seal/seat...
• A plug has backed off its seat and/or its insulator is cracked/leaking.....

 

And I'd add to the above list a broken exhaust manifold stud or bad exhaust manifold gasket.

Since you mention the CEL is on, check the diagnostic codes and post them here. But also keep in mind that noises are VERY difficult to diagnose over the Internet. Your "chuff" could be my "tick".

-Rod

 

You could quickly pull the plug wires (from the coil pack end) one at a time and see if there is NO difference in performance when you pull each one.

This would eliminate the plug question.


CMOS

 

Just to clarify, you'd actually want to note a difference in each wire you disconnect. If you find one that DOES NOT make a difference, that cylinder is not contributing.

-Rod

 

Ok heres an update. I took it in to a local repair shop today. They didn't put a scanner on it to check for codes yet but they did do a compression test. All the cylinders showed around 150 psi except the #1 cylinder which showed 0 psi! Zero! Zip! They said the needle didn't even move! Tomorrow they will do a leak down test on that cylinder but I suspect they will find a leak through the intake valve , judging from how quickly the intake plenum warmed up and the sound it made seemed to be coming from within the plenum itself when it was running.

Crap. This truck has only a little over 90k miles on it. Before it started this problem it ran like a top, and from one turn of the key to the next, instant problem with no warning. Any ideas what I may be up against? Sheesh, I really don't need an expensive repair right now.

Thanks to all,
Nitro

 

Nitroman.

Unfortunately when you lose a valve like this it requires the head to be removed.

I had a suspicion this was your issue, but I was hoping to be wrong....

As an after thought, I hope you have not collapsed a ring or holed the piston... Philip

 

It looks like the engine will have to be removed to correct the problem. Thank you Ford for designing an engine with the cam chain drive on the back of the head on the number one side. Nobody I talked to so far has had this experience. Even had Ford tech's say they were surprised to hear of such a problem occur at such low miles. I purchased this truck with 78,000 miles on the clock but only after extensive research led me to believe that this was as trouble free an engine as one could expect "legendary reliability" my a**. I only put 12,000 miles on it in the last two years Up to this point I have been a Chevy guy. Yeh sure, anything can have its share of quirks and problems but this is the first as well as the LAST Ford product I will ever waste my money on. Only 90,000 miles on the clock and it took a s$$t on me? My trusty '86 Chevy pickup with 245,000 miles on it still runs like a top with nothing more than regular maintenance.

There. Rant over. Please continue with your regular programming.

Nitro

 

Nitro, Hi a fellow Ford owner with problems as well. I have an 03 Exploder, that also from one key turn to the next took a s$$t on me. My problem though was with the timing chain, tensioners, and now camshaft positioning tools...$$$$....I have 130k on the engine and when the chain broke as I started the car it bent every valve, busted the valve cover, and I never even pulled out of the garage!! there are 2 chains one in front(can be replaced without pulling the motor), and one in back(MUST PULL MOTOR...Get ready to grab your ankles$$) and 3 tensioners, which by the way are made of plastic??? Anyway to make a long story short, nearly $2000. later still no vehicle. Now its not firing, pulled the motor twice now, so if and when u get yours repaired while the motor is out you should definitely think about replacing chains(Grab ankles please$) and tensioners(making sure tensioners are the uprgraded one from Ford..?($grab your ankles again please$) the upgraded ones are made from more durable Nylon and should not shread off like the plastic ones. Good luck on your service and hopefully you wont have to go through the same problems I have with the crappy 4.0 SOHC that Ford should have recalled, cause its to my understanding that every model since 1998-2006 with 4.0 SOHC have this same problem repeatedly. Ford had a silent owner notification and if you complained they would repair up until 100,000, if not, the costly repair was left up to the owner. Good luck!!