I bought my truck 99v10 5spd 4x4 with about 55xxx almost a year ago. I have added leveling kit, airaid tb spacer, k&n and changed muffler. About 2 months ago I went out to start it, fired right up with an instant knocking noise and horrible idle so I shut it off. popped the hood had a look everything seemed fine started it again and all was fine no knock Idle was fine went to the store and back home. Got up the next morning started it up no knocking but had a horrible miss in the idle and rpms below 2500. Drove it to work where I am a car and truck accesory installer and hooked up our diagnostic computer and no codes. After about a month of guessing the problem and reading forums such as this one I replaced plugs, o2 sensors, egr, Idle air contol valve, fuel filter and pvc. Then finally I started to get codes for random misfire and 2 and 9 misfire. Purchased new coils a few days ago put them on and no change. no more misfire codes but truck still has a horrible Idle ranging 500-800 rpm with like a....best way I could describe it would be the noise the exhaust makes when you put your hand over the tail pipes. this noise is constant well into the higher rpms as well. very sluggish and no power. If i let the truck idle for more than ten minutes it will start smoking real bad.(white with a smell I couldnt describe) Leaving it to idle it will not stop but if I go drive it for about a mile it will stop smoking. Driving it doesnt start the smoke only the idle.

I am going to stop here with the description so far as to not confuse anyone or myself. PLEASE feel free to ask any questions and I will greatfully take any advice.

 

Sounds to me like you may have a clogged catalytic converter. Disconnect the exhaust system ahead of the converter and see if your idle doesn't improve.

 

I have done that a couple times now hoping that would be the problem, but nope same thing just louder.

 

The only time I have seen an engine sound like that and not have an exhaust restriction was when the camshaft had gotten out of sync with the crankshaft.

 

I dont know how much this would matter but the the temp reading on the cat at operating temp would be less than a 100 degrees. you could hold your hand on it where as the pipe before or after you couldnt touch it. Once the smoke started it would rise to 200-250

 

thats because of the misfire, unburnt fuel is building up in the cat, then it ignites.

is it an intermittent problem or is it always happening?

 

its always there sometimes worse rarely better but always there.

 

I'm stumped. Is it possible someone put something (like sugar) in the tank, which has injectors clogged? I am just throwing it out, I don't know if it would cause your problems.

 

I was wondering that too but i have a locking gas cap, no enemys and fuel system seems to be working fine. I am at the point to take it to ford but I cant afford it right now after purchasing the coils. Ford wants 150 to hook it up to their diagnostic machine only problem Im seeing right now is it isnt throwing in codes so what would I be paying them to do you know?

 

Have you checked your coolant level? Does your oil look milky at all? Could be a coolant leak. White smoke, sweet smell. Low compression on 1 cylinder could cause a miss.

 

coolant level good, smoke definately doesnt smell like coolant. and oil still looks new I used Amsoil

 

My understanding is that the truck stores misfire codes that won't show on some scanners (like the auto parts store uses for free checks). I understand not being able to afford the $150, but pretty soon you may have to go to Ford.

 

not using a cheapo scanner we have a high quality scanner at my work that im using. Random misfire and 2 and 9 misfire is showing again. I will check the coil wiring in the morning. Also I was messing around with the test functions on the scanner last night and it showed a fault in the EVAP can vent flt. Could this be the problem?

 

Probably not.

 

Might want to check the boots and the plugs for #2 and #9 as well. See if you got any water down in there.