ccculbreath

Hey guys and gals,
I have a ‘99 f150 4x4. Last Monday we received a trouble code PO303. I have replaced coil pack, spark plug, TPS , and fuel filter. No vacuum leaks and the injector is good. Does any one have any idea what’s going on with this truck?
Thanks in advance...

whitecrystal1

See below
http://www.obd-codes.com/trouble_cod...e-detected.php

ccculbreath

I have to say the eye thing is pretty creepie. thanks for the site. i'm trying to get there but my browser times out, so i'll keep trying ... thanks again!!!!!

whitecrystal1

lol, It was woking when I first posted it here it is again http://www.obd-codes.com/trouble_cod...e-detected.php if it still doesn't work it's ok, I posted the info in it below.
Is your truck running ok and just showing a light still? If so, try resetting it and see if it comes back. If not, there are a few other things listed below you can still check.

P0303 Code - Cylinder #3 Misfire

Technical Description

Cylinder #3 Misfire Detected
What does that mean?

A P0303 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #3.
Symptoms

Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes

A code P0303 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors

ccculbreath

the fuel injector is clicking and it sounds like all the others. i have removed all coil packs and plugs cleaned them and put them back in with new coil pack and plug in cylinder 3. the night before this started it was runnig great, it turned cold and rainy the next day and we did not drive it. monday morning is when it started doing all this. i really do not think it's a burnt valve, the plugs and fuel filter was changed back in the summer so i don't think it be those. if you could tell me more about the rotten egg smell comind from the exhaust? the exhaust does have a different smell but it hasn't struck me as rotten eggs. i'm wanting to lean toward the pcm but i just don't know...

whitecrystal1

When you replace the coil on #3 did you replace the plug again? Did you see any mositure in the well? did anything get wet.

ccculbreath

yes but it was not coolant

whitecrystal1

OK, If I'm understanding this right, you had moisture in the well You replaced the coil but not the plug. Go buy a new plug for #3 cylinder Take the coil back off dry everything out completely replacing it with the new plug. Why you have the coil off (even though it's new) inspect the boot and the connector inside of it. Apply some dielectric grease to it and reinstall it. Pull the negative cable off the battery for at least 30 minutes to reset the cpu.
Did you mess with the MAS at all. If so make sure it's installed properly If not clean it before you try to reset the cpu.

ccculbreath

no,no,i did replace the plug in #3 and cleaned,dried,and regapped all the other plugs. and i removed the boots off of all the coil packs; cleaned'em, dried'em,and put the di-eletric grease in them and reinstalled them all. i changed the TPS, and the fuel filter. fuel flow was about 50 psi before starting and 30-45 psi after start up and idle. i also checked for intake manifold leaks with propane. i clear the code and it will come back within 100 miles.

ccculbreath

no no, i did replace the plug in #3. i aslo cleaned and regapped the other 7. i also replaced the coil pack in #3. and removed the other 7 coil packs, removed the boots,cleaned and dried them, put di-electric grease in them and reinstalled. i also changed the TPS and the fuel filter.and checked for leakes around the intake manifold with propane.