Throwing p0302 in my 2002 4.7l. I have replaced the plugs and the coil for that cylinder. I unfortunately put in platinum plugs, so now I will be buying new plugs. Also when starting if I get in and turn the key right away, as opposed to turning to run and waiting a few seconds, it cranks over a lot longer. It also idles rough and is slow to respond to the gas first thing in the day. Have been getting the misfire code before the plugs were replaced, after, and after the coil was replaced. Any help would be great.


Note: Just plugged in the noid light and it seems the electrical side is fine.

 

First off welcome to the forum!

Second...... You have the 4.7L so platinums aren't the worst for it but I hate them. I will tell you to go to Champion Regular Copper Plugs (OEM) or Champion Truck Plugs for a better burn.

Third...... It sounds like a fuel pump. Yours might be bleeding back to the tank and leaving the line unpressureized and out of fuel. You turn the key which starts the pump and leave it there for a couple of seconds that re-primes everything then she starts great. If you don't do this she has to crank over while charging the line finally starting the truck. In the morning push the pressure test port on the fuel rail (looks like a tire valve) and see if fuel sprays out under like 54psi. If not replace the fuel pump. Be careful not to get it in your eyes!

Give us an update!

 

Ok, haven't changed the fuel pump yet. Still trying to get p0302 to go away. Like I said earlier, replaced, the coil, spark plugs and now have a new injector in there, still get the code back. Any more ideas?

 

Ypu pluged noid into INJ and or COIL? fine means it flashes- yes ?

Some basics...remove #2 plug - how does it look? dry- wet- black - gray hopefully to new to tell- Then we want a noid light (test light ) to check the #2 inj pulseing?
At the #2 coil check the ground also PCM signal- this is an internittant 12v a noid would work or a dvom

Get your self a fuel pressure gauge, test pressure- key on eng off-eng running - then turn off observe pressure - should be steady you are testing leak down. Gauge is often availableas a loaner or rental at parts suppliers.

You should first ck the above components inj and coil throughly...then if good fuel pressure- injector (new) is pulsing, coil (new) is pulsing, a compression test #2 cyl....as well as a ck for vac leak-

IMPORTANT -vehicle is STOCK?

ps: TRYING TO add much and be clear - this post help?

 

Plugged the noid light into the injector yes. Did not in the coil. Vehicle is stock. Pulled plug while I was changing injector and double checked the gap. Plug looked fine. Engine light will stay off for quite a while after code is cleared. Seems to come back after the first start of the day on a rough idle.

 

Check the harness for water or corrosion. You might need to spray it with contact cleaner to dissipate water and clean the harness connections.

 

which connector? inj or coil firewall?

 

Didn't see any corrosion or any signs of water but sprayed the connectors for the coil and injector. CEL stayed off for about a week but now its back with the same code 0302. I am at a loss. Could the fuel pump be causing this? If so how come its only misfiring on cylinder 2?

 

It was the harness for the injector on the injector.


Could be the fuel pump. Try a pressure check and you should be over 50psi. New is 54psi and at 50psi I've told everyone to replace it even tho the service manual says 40 something. Could also be rust in the fuel line as I've seen that before. #2 is a classic as well as #7 for notorious injection and fuel and also TPS issues. Clean the TB as well including the IAC valve for good measures if you haven't already.

 

what tool do I need to check the pressure on the fuel rail? Also I only have 44k miles on this thing how likely is it the fuel pump? I really dont want to drop another 250$ into this thing since im trying to sell it. If worse comes to worse I guess I will but am hoping for cheaper alternatives first.