Crankshaft sensor ... engine stumbling. 1999 3.8

[12Ounce]

1999 3.8 engine 261k miles. Crankshaft sensor failure.

Six months ago the engine began "stumbling" very infrequently. Over time it happened more and more. Finally the engine did not want to be loaded up ... did not want to accelerate or climb hills. But this was sometimes not the case ... sometimes, the engine would run fine for brief periods. Never was cranking or idling an issue.

Even tho the stumbling became quite severe ... there never was an engine code. At least, there was no CEL.

Because of a recent experience with S's Escape:
http://www.automotiveforums.com/vbul...d.php?t=957259
.

... I went for the crankshaft sensor early. DID THE TRICK! All seems to be OK now. Hope this helps someone.

[Lbert]

Thank you for sharing the experience.

[12Ounce]

Well, I posted the "good news" too soon!

The new crankshaft sensor did make things much, much better ... but as I later took a long ride, I found the old "infrequent stumble" was still with me. It was as if I had turned the calendar back 6 months! ... and still no CEL! So disappointing to have the stumble, and with no CEL to help diagnose. My AutoZone folks won't even walk out the door with the scanner unless the CEL lamp is lit!

Then I had an idea ... If a code were "induced", would it cause other faults to be reported? I removed and plugged the control hose to the EGR valve, and drove 10 miles or so until the CEL turned on ... then drove straight to AutoZone to get the codes read. Of course, the EGR codes were there ... and so was misfire codes for cyls 2 and 6! BINGO! Now, I knew the center coil ( for sibling cyls 2 and cyls 6) of the ignition pack was faulting! Even tho the coils read closely when checked with ohmmeter ... and I could see no surface tracking or cracks ... the 50k mile-old coil was replaced.

NOW! I have driven a number of miles ... gunned it several times. Seems OK!

[wiswind]

Seems those coils are right up there on the fail list.