so here we go... it's a 99 F-250 w/5.4l Triton... it's a work truck in the oil patch so it sees a lot of abuse :) yesterday it ran fine and today when i went to do my daily run-about i noticed it was lacking a lot of power... and sounding way under powered as well. i know enough about motors to know what to check for as far as usual suspects but to no avail. when it's sitting at an idle it makes a huffing sound... like when you have a bent push rod and your valve sticks... but it's comming out of the exhaust, not the intake... so i'm thinking maybe a valve is stuck on the exhaust... but i'm not 100%. i went to do a compression test on it, ya know... pull the spark plug out and hook up the guage but there are no spark plugs? i know i'm gonna look like an idiot for saying that but really, no spark plugs... i see the injectors and beside them is a little cap that i'm guessing is some sort of sparking device. do these just pull out and there is your spark plug? it seems to be burning more fuel and the oil needs to be topped up every week or so but the exhaust doesn't smell like burnt oil or have a fuel smell to it. if i hold my hand in front of the tail pipe it sucks my hand in and then blows it out at a fairly rapid pace. if you rev the engine up to 1000 rpm or more it seems to go away but i'm not sure that the problem is really solved, i'm just thinking there is more exhaust comming out and it's hiding the "suction". any ideas on where to start?

thanx

Hi,

Honestly I don't know where your spark plugs are, any shop manual for your truck should show you where they are. Off the top of my head they are either screwed into the sides of the heads or they are somehow embedded in the valve covers.

Ok, a little theory... Right as the exhaust stroke ends and the pistol starts to travel back down at the beginning of the intake stroke there is a very short period of time where the Exhaust valve and the Intake valve are both open at the same time. With most engines in daily driver cars/trucks this is so short that no one ever notices it, this is where the vacuum you are feeling in the tail pipe is coming from.

It sounds like your timing belt either jumped a tooth and now the timing is off and the piston is not where it is supposed to be in relation to the valves opening and closing, or you burned an exhaust valve and now it has a hole in it.

Check the timing and do a compression test on your engine.

the little caps you speak of... are in fact individual coils, and the system is called Coil On Plug; locating the plugs shouldnt be too difficult now.
I think your having a problem with engine sludge. I work in Ford, and I've seen too many 5.4 tritons lately with a great amount of sludge evident on the filler cap... engine sludge can have serious effects on the engine, causing increased friction and even siezing... you might concider flushing the engine and switching to a synthetic oil...the triton is apparently prone to sludging, and a synthetic is one of your first lines of defence against it.