Newbie here. Great sit everyonee. I think i have water in my fuel.I have a 2005 997 and about every 12 or 13 miles its cuts out 2,3, or 4 cylinders. I can turn the car off and let sit for a couple of min. and it runs normal for a while then cuts out again. The car sat for 3 wks.in the garage and i did not crank it but at the same time we received 22 inches of rain in 4 days. I have ran 2 bottles of heet in the tank with no luck. My local tells me to run a bottle of seafoam to get rid of the water. I have also put in 1 small bottle of techron. Please help if u can. Thanks

 

Several years ago I had some "cutout" problems with my 06 at about 4-5000 miles od and the dealer did a scan, found nothing , said it might be a tank of "bad gas" so I ran it down to empty and refilled. Same thing a few weeks later, another scan, again nothing. Service manager ( they still had a good one back then ) looked at the results and told me that I needed to run it harder. Anyway, started running it up to 7000+ in first and 2nd and then did a few 6-10 mile stretches in 3rd at about 115mph. Never had a problem since, but I am tired of replacing my rears every 9000 miles.

 

Pretty unusual with today's cars to have rain water enter the fuel system unless the fuel filler cap was left off. Water in the fuel system is more likely the result of condensation. If you keep your fuel level in the tank low most of the time, the greater surface area on the inside of the tank will promote condensation. The low fuel level combined with changes in ambient air temperature will cause water droplets to form. Also, heated fuel being returned from the engine with a low fuel level and cool/damp conditions will promote condensation.

When in doubt, pump it out......If you suspect water in the fuel system, the tank should be drained. Cheaper than buying new injectors....

 

Although unlikely, I would check the airbox to see if any water has accumulated inside. The early '05 airboxes did not have a drain membrane and were later swapped out. It's possible water came thru the decklid into the black snorkel and led to the box.

More than likely---I'd suspect the coil packs are starting to go. If you're getting a CEL due to misfires on 2,3,4 cylinder banks you need to get these checked out. After 5+ years these things start to go........

 

My 05 997 starts mis-firing after 12 0r 13 miles. This is happening on a regular basis. I can turn off ingnition and re-start and it runs fine for a while. New plugs, new air filter and cleaned the maf sensor.Will scanners pin-point the exact problem? Thanks

 

"I'd suspect the coil packs are starting to go"

Agree; I would test the coil packs. If you had water in your fuel starting & restarting would not solve the issue as the water would still be present.

 

As others stated it may not be related to fuel. Note though that ethanol-laced gas (E10) is hygroscopic. Water builds up in the tank especially if the car sits with a partially filled tank.

 

Wouldn't it seem odd that 2,3or 4 coils going-out at the same time?

 

Given they have all been subjected to the same lifetime / environment; no. But you need to test one to see if they are really failing.