Po305
08-17-2018, 05:59 PM
#1
Thread Starter
Join Date: Aug 2018
Location: Georgia
Posts: 23
Po305
PO305 cylinder 5 misfire. Okay so I pulled the plug and it had water on it I sprayed it out, did pressure test found no leaks around intake... I cut the code off and am going to see if it comes back on if it does and doesn't have water I'm going to replace spark plug. If it does have water im going to have to replace intake manifold? Suggestions, help!
08-17-2018, 10:12 PM
#3
Thread Starter
Join Date: Aug 2018
Location: Georgia
Posts: 23
The code hasn't came back yet. Idk where the water came from.. I know if you switch to another and it does it it's probably the plug wire. I'm going to wait a week while monitoring codes and see if it comes back. If it does and doesn't have water im change plugs and wires.
08-18-2018, 11:57 AM
#4
2nd Gear Member
Join Date: Mar 2015
Location: Oregon
Posts: 188
Just verify, cylinder #5 is the one on the driver’s side bank closest to the front of the car? Does your car have the original manifold with the plastic coolant crossover pipe? And what MustangDude said...if the code comes back and the spark plug well is dry, swap the coil pack with another cylinder, clear codes and see if the code comes back but on the cylinder to which you swapped the pack. If that’s what happens you need a new coil pack. It’s not likely a problem with the spark plug.
08-18-2018, 02:25 PM
#5
Thread Starter
Join Date: Aug 2018
Location: Georgia
Posts: 23
Yes and yes it's the original intake which I know they are famous for leaking because of the plastic coolant cross over. And the coil pack isn't but probably 3 months old I change it out when I got the car because the end connector was broken where it plugs. But I mean it could of crapped out, I'll try what y'all said if code pops back up.
08-18-2018, 03:09 PM
#6
4th Gear Member
Join Date: Nov 2009
Location: SoCal
Posts: 1,826
If you had coolant in the plug well then that's your problem. No sense spending time moving coils around or anything else until you figure out why there was coolant there and make it stop (which I can assure you will not do on its own).
Probably time for a new manifold and gasket set. What year is your car, since you have the all plastic manifold then I assume 2001 or earlier? When you get the updated manifold you will also need an alternator bracket to go with, as that was also changed slightly. Not very expensive, adds like $15 to your parts bill.
Probably time for a new manifold and gasket set. What year is your car, since you have the all plastic manifold then I assume 2001 or earlier? When you get the updated manifold you will also need an alternator bracket to go with, as that was also changed slightly. Not very expensive, adds like $15 to your parts bill.
08-18-2018, 05:06 PM
#8
Thread Starter
Join Date: Aug 2018
Location: Georgia
Posts: 23
Haven't been losing coolant either and hasn't been running hot. But like I tell people it'll get worse before it gets better. I'm check the plug for water again this weekend. Might just go ahead and replace intake heard the factory ones are famous for leaking.
08-18-2018, 05:26 PM
#9
2nd Gear Member
Join Date: Mar 2015
Location: Oregon
Posts: 188
The leaking doesn’t happen all the time and you can’t really diagnose with a pressure test IMO. It seeps. And it doesn’t take much to fill the plug well. Like Z28KLR said, if it’s coolant in the plug well, dollars to doughnuts it’s a failed coolant crossover and the manifold needs replaced. So that’s really step one is to verify it’s coolant...and it probably is...unless somebody is pouring water in there while you sleep. 
08-18-2018, 05:34 PM
#10
Thread Starter
Join Date: Aug 2018
Location: Georgia
Posts: 23
Haha 😂 damn neighbors... but I found what I need. Comes with alternator bracket, thermostat everything and it's on sale! Thanks so much guys! I'm new to this and y'all have been a great help! https://www.carparts.com/details/Ford/Mustang/Replacement/Intake_Manifold/1998/GT/REPL311902.html?TID=gglpla&origin=pla&gclid=EAIaIQ obChMIkdOP8If13AIVhpOzCh1pew98EAQYAiABEgILy_D_BwE& gclsrc=aw.ds