longhaul

Going to pick up from the dealer-they said they found nothing. Already bought a can of seafoam, I'll try that.
As to MAF,etc I am clueless on that stuff . I do have a real time programmer and code reader-I'll try that. New fuel filter by the way.
Yes, valves tap after 200K, but 20,000? I know there was aTSB on this, got to find it. Real noisy until warm.
Ddi check all plugs for tightness...
Again, it's abugger-only happens under load, and only sometimes. Love those kind of problems!!!</sarcasm>

A_J

Another "just thowing it out there" - cam phasing?

I know that with the BMW E36's like I had, one cause of misfire in a certain RPM range was the cam timing - in both that and the 4.6 those are driven off oil pressure, and it's controlled via a solenoid in the 4.6..

22kart22

true. 20,000 miles is nothin.


I have no idea.

If all else fails you can always go to your dealer!

The Ghost

Make them change the plugs...I had this exact same type of problem and it was fouled plugs. I'm sorry, I didn't look where you are from, but ethanol is becoming popular in a lot of warmer states as an additive for fuel. Our cars apparently hate the stuff. I changed gas stations and never had another issue. Went through two sets of fouled plugs before 20,000 miles.

22kart22

My dad works for exxonmobile and here's the scoop.

In the summer, our pump gas is reformulated to contain more ethanol to lower the levels of smog in humid, condensed places.

And when more ethanol is added, your fuel economy skydives since the caloric content of ethanol is much less than that of gasoline.

Our engines also dont like high ethanol, so one thing you can hopefully try is to put a higher octane fuel in your car just to try it.

longhaul

Good advice-I'll give it a try! Ethanol is everywhere here. My powerstroke ford Hates[sm=bounceybounce.gif] bio-diesel-go figure. So I know fuel choice can be a problem. Many of the stations around here use "pipeline" fuel-generic stuff from a distributor. Most are up to 15% ethanol.
Appreciate the input,everyone. If I find a definative problem, I'll let you know! Just got it back fron the rocket scientists I call a dealer...

longhaul

Anyone know who's the cheapest for plugs. It seems I found ones ranging from several dollars (normal old style plugs claiming to fit) to twenty bucks? What gives?

22kart22

get good ones, like autolites or bosch.

toolttime

If you use octane booster in your car plugs is the problem. Happened to me

moosestang

Evolution performance has them for $80 a set I think.

http://www.evoperform.com/shop/

What plugs were claiming to work on the new mustangs?