I used to know about cars and how to fix when engines were simple gas with carburators. I now have a diesel Chevrolet colorado with automatic trans and when I place it in gear [drive or reverse] in idle mode, it sometimes dies. In a gas car with a carb, I would simply up the idle with a screwdriver. Not so easy any more with the onboard computers and our local mechanic says that I have to go into the Chev dealer and get a computer diagnostic and most likely replace the on board computer @ 10Kthb+. <deleted>!!

Surely there is a way to up the idle on a diesel motor??

The Chev colorado is simply an isuzu and uses isuzu parts...but charges more, right??

Could be the automatic air idle valve (think thats what they call it), or a leak in the hose from it. The valve controls air to the intake to keep idle constant with any loading.

PS. Perhaps different on a diesel but sure there must be one. (l think)

Idle on commonrail is 100% ECU controlled. Could be as simple as a bad or fouled sensor - plugging it into the proper Chev and/or Isuzu diagnostics should reveal the problem quickly. If you're concerned about getting ripped off, at least you can try both brands for a 2nd opinion

Your Colarado is probably less than two years old. Why is this not covered under the warantee servicing?

Your Colarado is probably less than two years old. Why is this not covered under the warantee servicing?

Chevy Colorado from 2006 to 2011 all have ECU controlled idle, so rather than picking dieselsystem apart to find fault, plug in the diagnose at Izu or Chev and fault will probably be dsplayed within 10 seconds.

Colorado 2004 to 2006 are old style diesel, but still with OBD to diagnose as first attempt to display fault

Your Colarado is probably less than two years old. Why is this not covered under the warantee servicing?

Sorry I thought the Colarado was only a couple of years ago.

Your Colarado is probably less than two years old. Why is this not covered under the warantee servicing?

Sorry I thought the Colarado was only a couple of years ago.

Don't feel so bad, most Thai's only discovered it in the past year

(used prices for Chev pickups have increased by 50-100K in just 6 months)

to be more precise, it's a 5 yr old '3.0 TD commonrail intercooler'........that's the old model??

Yea, I'm scared just to go into the dealer and have them say that I need the whole onboard computer @10Kthb just because they are too lazy to check further or need to make their monthly parts sales quota.

The first thing I would try would be to change the fuel filter and see if that makes a difference ? Next would be to get the dealer to plug it in and see what they say. You don't have to take their advice or let them fix it. A plug in and diagnose shouldn't be that much.

to be more precise, it's a 5 yr old '3.0 TD commonrail intercooler'........that's the old model??

Yea, I'm scared just to go into the dealer and have them say that I need the whole onboard computer @10Kthb just because they are too lazy to check further or need to make their monthly parts sales quota.

Commonrail is the "new" diesel system.

Reading the diagnose is very simple, and I believe they wouldnt try to sell you a new computer if there is a faulty sensor or leak. New computer wouldnt make any imrovement if sensor/leak is still faulty

The first thing I would try would be to change the fuel filter and see if that makes a difference ? Next would be to get the dealer to plug it in and see what they say. You don't have to take their advice or let them fix it. A plug in and diagnose shouldn't be that much.

dirty fuel filter would not cause idling problem but high rev problems, and is warned on dash by yellow/orange light

The first thing I would try would be to change the fuel filter and see if that makes a difference ? Next would be to get the dealer to plug it in and see what they say. You don't have to take their advice or let them fix it. A plug in and diagnose shouldn't be that much.

Would a simple mechanical fault like a dirty fuel filter show up on the Diagnostic computer??