Chrysler Repair: 97 2.5L V6: rpm loss momentarily, 4 digit numbers, gas consumption

Question
What are the most common causes when the rpm's suddenly drop to zero while driving at or below 60 mph speed limit? It has happened sporadically for about 3 months, maybe once a week and some weeks not at all. Yesterday worse than the other times in that it took a bit (in terms of seconds) longer to "come back" than before. Engine does not shut off, does run just alittle bit rough all the time.  99,000 miles; know it will or maybe does need spark plugs & timing belt soon.  Has a new battery and belts except for timing belt. Gas consumption has been higher than normal for about a year but the engine runs great and it's not hot. No dash warning lights; no fault codes when the new battery was put in about 6 weeks ago.

Answer
Hi Carol,
When you say rpm 'drops to zero' is that literally what happens? I assume that the engine rpm doesn't really stop that quickly or does it? If not, then it is a loss of power (engine slows but rpm doesn't go to 0); if the gauge drops to 0 rpm then I would suspect an electircal disconnect related to the ignition switch that is cutting off the electronics to the rpm meter.
You might get another code readout, for free at an Autozone parts store. While the '97 year was transitional as far a code readout is concerned, try the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, puase, flash, etc. Count the flashes before each pause. Then repeat the process to assure an accurate set of counts.  If it doesn't do that then does the mileage reading of the odometer instead change to show some 4-digit numbers? Neither may happen in which case only a readout with a plug-in code reader will work. I would believe you should either find a new code or you have an interuption in the ignition circuitry.
Roland
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