Got some strage behavior from my 2001 Supercrew. I was stuck in bumper to bumper traffic for about 45 minutes. First thing I notices was that the idle increased a couple of hundred RPM (usually 600 when in drive and was running 800-850). The next thing that happened was a strange humming sound came from under the hood. Then when the noise stopped, the engine died for an instant (RPM to zero, no warning stumble) and bounced right back. It kept doing this until I had gotten out of the traffic and was able to drive for a while.

The motor idles smoothly without a noticable miss. I can't hear any pinging. It isn't throwing a code. It drives fine for extended (200 miles) period on the highway with no problems. Don't have any trouble with in-town traffic (except bumper to bumper listed above).

Another new and wonderfully strange behavior that may be related is that when going from drive to park or neutral the engine seems to surge for a second, the RPMs bounce or flutter for a second, then it settles into the propoer place.

Someone mentioned something about an idle control "valve" or somesuch perhaps being the problem. Any of this sound familiar to anyone?

The mods to my truck are (don't know what might affect this so listing all):

1. K&N filter (clean & I'm sure of it)
2. Synthetic fluids everywhere (recently done)
3. Superchip
4. Flowmaster Y pipe replacing stock
5. Flowmaster series 40 Delta flow replacing stock

Thanks for any help!

Chuck

 

If all of the idle equipment (valves & sensors) are OK, you might consider getting the tranny checked- assuming it's an automatic. Could be that it isn't slipping enough to allow the engine to idle in "Drive". Does the truck die when idling in "Park"?

Happy Holidays! :-X12