Skipping

Tiny
JACK DAVIDSON
  • MEMBER
  • 1999 ACURA TL
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 180,000 MILES
I installed a new EGR valve, cleaned the intake manifold including the EGR port. Put SeaFoam in the gas, oil, and a little thru the vacume lines. I'm not getting any of the P0300 thru P0306 or P0401 DTCs anymore. BUT I'm still getting the P1399 DTC w/ a mild skip under load. The plugs are new Bosch 4428 +4 PLatinums What else could be causing the P1399? Or do I just need to let the SeaFoam work its" way thru the systems?
Do you
have the same problem?
Yes
No
Monday, April 4th, 2011 AT 12:45 PM

11 Replies

Tiny
KHLOW2008
  • EXPERT
P1399 is a temporary code for misfiring and the misfiring code should be back sooner or later.

What is the plug gap setting?

Have you tested the coils?
Was this
answer
helpful?
Yes
No
Monday, April 4th, 2011 AT 1:11 PM
Tiny
JACK DAVIDSON
  • MEMBER
The Bosch 4428s are the "NO-Gap" style plugs and I haven't messed w/ that. I was going to test the coils if I kept getting specific misfires (P0301-P0306), but those DTC(s) went away. Now it just the P1399. Is there a specific procedure to test the coil itself, other than faul isolating thru the wiring between the plug-connector and the ECM? I can do that, but didn't want to as there's no specific misfire to id which cylinder I should testing?
Was this
answer
helpful?
Yes
No
Monday, April 4th, 2011 AT 1:21 PM
Tiny
JACK DAVIDSON
  • MEMBER
Additionally, someone told me to replace the Bosch w/ the NGK(s). I thought the Bosch were pretty good plugs. But if they're part of the problem, I'ss certainly replace them.
Was this
answer
helpful?
Yes
No
Monday, April 4th, 2011 AT 1:37 PM
Tiny
KHLOW2008
  • EXPERT
The gapping might not be as specified. I would try replacing them first to see if it solves the problem.

Have the compression tested if changing the plugs does not help.

Coils can be tested for resistance but if it is misfiring on all cylinders, the likelyood of all coils failing at the same time is almost zero.

Apart from compression, check the fuel pressure and exhaust system.
Was this
answer
helpful?
Yes
No
Monday, April 4th, 2011 AT 8:23 PM
Tiny
JACK DAVIDSON
  • MEMBER
Thnx-a-million. I'll put new NGK(s) in and see.
Was this
answer
helpful?
Yes
No
Tuesday, April 5th, 2011 AT 12:43 PM
Tiny
KHLOW2008
  • EXPERT
You're welcome.

Good luck and have a nice day.
Was this
answer
helpful?
Yes
No
Tuesday, April 5th, 2011 AT 1:34 PM
Tiny
JACK DAVIDSON
  • MEMBER
Put in new NGK Platinum plugs gapped to.44, but still getting multiple misfires. Can't do compression check myself and not getting any codes for fuel delivery system errors. So I gotta go to my pro I guess. Thnx for all the help guys!
Was this
answer
helpful?
Yes
No
Wednesday, April 6th, 2011 AT 2:29 PM
Tiny
KHLOW2008
  • EXPERT
Did you check the fuel pressure?
Was this
answer
helpful?
Yes
No
Wednesday, April 6th, 2011 AT 3:54 PM
Tiny
JACK DAVIDSON
  • MEMBER
No. But a mech friend said if one Coil/boot causes a misfire it sometimes confuses the computer & reports multiple cylinders. He suggested unplugging coils 1-@-a-time while idling to see if I can isolate the skip to a single cylinder. Duh! I should've thought of that istead of relying on the DTC to try and isolate. Thnx.
Was this
answer
helpful?
Yes
No
Wednesday, April 6th, 2011 AT 5:51 PM
Tiny
JACK DAVIDSON
  • MEMBER
That was it! Unplugged #2 cyl w/ eng idling and got no chnge. All others RPM(s) dropped. Swapped coil w/ #5. Now no change in RPM when #5 unplugged. Replaced coil. Skip gone! So. EGR fixed, intk mnifld cleaned. EGR prt cleaned out. Good NGK plugs. Skip GONE! Runs like a new Singer Sewing Machine! Thnx for all the help!
Was this
answer
helpful?
Yes
No
Thursday, April 7th, 2011 AT 4:42 PM
Tiny
KHLOW2008
  • EXPERT
You're welcome.

Glad to know you have fixed the problem.

Have a nice day.
Was this
answer
helpful?
Yes
No
Thursday, April 7th, 2011 AT 5:51 PM

Please login or register to post a reply.

Recommended Guides