LOOPES AND BACKFIRING WHILE IDLE

  • Tiny
  • Tmaj9447
  • 2002 FORD F-150
  • 308,000 MILES

Hears the deal; this all started when I changed the spark plugs. Truck ran fine I was just doing pms. Changing the plugs ended up with having to rethread one of the coil pack bolt holes in the intake. One that was repaired I installed new upper and lower intake gaskets, torqured everything to specs, installed 2 new coil packs (broke 2 getting them out), replaced all 8 plugs with ngk oem replacements, buttoned everything up and to my suprise this lopeing and sounds like intake backfiring. Please help! Engine is a tritron 4.6

Do you
have the same problem?
Yes
No
Thursday, May 24th, 2012 AT 9:53 PM

7 Replies

  • Tiny
  • Rasmataz
  • MEMBER

Go to this link: http://www.2carpros.com/articles/engine-backfires-while-running

Was this
answer
helpful?
Yes
No
Thursday, May 24th, 2012 AT 10:05 PM
  • Tiny
  • Tmaj9447
  • MEMBER

Checked fuel pressure at rail 40 psi

Was this
answer
helpful?
Yes
No
Thursday, May 24th, 2012 AT 11:33 PM
  • Tiny
  • Tmaj9447
  • MEMBER

If this helps rpm goes from 700 to 1500 radically.

Was this
answer
helpful?
Yes
No
Thursday, May 24th, 2012 AT 11:34 PM
  • Tiny
  • Rasmataz
  • MEMBER

Check for vacuum leak and clean the idle air control valve and see what happens

Was this
answer
helpful?
Yes
No
Friday, May 25th, 2012 AT 1:00 AM
  • Tiny
  • Tmaj9447
  • MEMBER

Okay still no change, I took the 4 spark plugs on the rightside out and they are sooted and dry. Should I check the injectors, seems like it is not getting fuel to the cylinders. Not sure

Was this
answer
helpful?
Yes
No
Friday, May 25th, 2012 AT 12:24 PM
  • Tiny
  • Tmaj9447
  • MEMBER

Lower intake gasket, replaced and runs as expected. Vacuum issue solved. Thanks!

Was this
answer
helpful?
Yes
No
Friday, May 25th, 2012 AT 7:05 PM
  • Tiny
  • Rivermikerat
  • MEMBER

Or pleasure. Happy to help.

Closing thread.

Was this
answer
helpful?
Yes
No
Friday, June 1st, 2012 AT 2:17 AM

Please login or register to post a reply.

Other Engine Backfire Questions