erratic idle

[outland1]

Just finished changing out the water pump on '04 CTT. Started her up and I got a fluctuating idle, up to 1500 down to 500 then rev's back up to 1200-1500. Took a little test drive to see if it would reset, but no luck. Ran well while accelerating, but cuts out when you take your foot off the gas and fluctuates when sitting a light. Then to make matters worse the PSM failure indicator flicks on, what the heck do those two have in common? Checked all the numerous hoses, pipes and electrical connections again. All looks well. Am headin' to the autoparts store for some MAF cleaner and Throttle body cleaner. I am out of idea's if that doesn't work. Any suggestions? Also changed coils all coils and plugs10k ago.

Edited March 6, 2011 by outland1

[diesel2fast4u]

Just finished changing out the water pump on '04 CTT. Started her up and I got a fluctuating idle, up to 1500 down to 500 then rev's back up to 1200-1500. Took a little test drive to see if it would reset, but no luck. Ran well while accelerating, but cuts out when you take your foot off the gas and fluctuates when sitting a light. Then to make matters worse the PSM failure indicator flicks on, what the heck do those two have in common? Checked all the numerous hoses, pipes and electrical connections again. All looks well. Am headin' to the autoparts store for some MAF cleaner and Throttle body cleaner. I am out of idea's if that doesn't work. Any suggestions? Also changed coils all coils and plugs10k ago.

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OBD codes would help!

[wvicary]

Double check the connections on the mass air flow sensors or a unmetered air leak.

[outland1]

Well the MAF cleaner didn't work. Cleaned all the electrical connections etc. No CEL, so no joy there. If one of the little black pipes or breathers had a crack, would there be a whistle or sucking noise? Back to square one.

[Loren]

Fault code(s)?

[outland1]

I hate to sound like a newbie, but are there codes even if no Check engine light? I am in a Porsche desert (Medford, OR) so no dealer available to pull codes. Guess it's time to buy the Durametric.

[wvicary]

You can fault code stored without them triggering a check engine light. Each code has it's own parameters for setting and or triggering the light.

[RFM]

If you have disconnected the throttle body completely and/or his connectors, the fault is likely there.

[outland1]

Well went to take it to the shop and reconnected everything one more time, ran perfect no idiot lights, CEL etc. Must have reset or something. Anyway thanks for help and will be ordering my Durametric.