Went thru a similar deal w/ '03 Ford Escape 3.0 V-6
Repetitive, fast hesitations (stumbles), lasting 1-2 seconds, varied in how far the "sets" were apart, it was more evident climbing a incline, while slowly administering gas. Random or none on level ground. Every now and again at idle, but very seldom.
---No codes --- (cleaned 1st, and/ or replaced the following
New Plugs. Then changed to "genuine plugs". Bah-Hum-bug, nothing wrong with the other new ones, I previously installed!
Boots and springs (possible holes in boots. NOT!)
A new IAC just for Giggles!
Mega Vacuum leak search several times.
Fought with wife many times over the situation, for 2+ months, It was NOT GONNA WHOOP ME!
I really hated taking off the "Plenum" so many times to access the other 3 cylinders
Each part seem to fix it for a day or two.I did not mind replacing the suggested parts, as I am all for "PM" and she's got 100,000 miles on her rig.
The final cure was #3 misfiring (lucked into the correct cylinder) I was gonna swap a new coil pack down the line, till it stopped
#3 was the ticket!
I had tried to get the Technical school to ride me with their portable machine---things did not work out, with their schedule.
I went to a salvage yard to get a used pack ($10) to swap around, then buy a new one if solved the problem.
The Master plan was to swap thru the front 3, if no positive results. Remove the plenum, "One Last Time", put the 3 front, EZily accessed packs under the plenum. Re-install it. Then swap thru the 3 front ones again (now the previous rear ones). THAT WAS THE PLAN ANYWAY.I HAVE PLENTY OF TIME, JUST NOT A BUNCH OF MONEY!
So happened, the salvage yard guy had a "SNAP ON" machine, he found a stored code, it said #3 had misfired. My little scanner could not tell me that!
Runs perfect now, with the New $79 Coil Pack!
That's why I'll always stick with a Jeep CJ, You can just about diagnose them, as you hear 'em drive by!
Monday, September 5th, 2011 AT 12:41 AM