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Discussion Starter #1 (Edited)
So, for about a few weeks now, if I'm either in drive or neutral, my truck begins to dip well below 400rpms and spiking to around 800 - 1000. This problem is only occurring when I'm at a standstill for roughly 7-10 min and continues unless I either get on the gas and go, or keep it revved up. Again it only seems to occur after a good 7 min or so. I'm also getting a rough idle which I heard can be normal. I don't want it to turn into a serious problem so I'm looking deeper into the situation.

Here are the things I've done:
Cleaned the TB
Cleaned MAF
Cleaned air filter
Sea foamed twice over past few weeks
( Can't be bad gas)


My engine light is on so I can post the codes within the next day but, I plan on running sea foam through the intake, and also cleaning fuel injectors in hopes of fixing it. Which will happen a few days from now when I have time.

THANKS FOR ANY ADVICE!
 

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Clean Fuel Filter and or Fuel Pressure regulator would be worth a look/see.
 

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Discussion Starter #3
Clean Fuel Filter and or Fuel Pressure regulator would be worth a look/see.

A few days ago I disconnected the hose from the intake to the fuel regulator, turned the truck on and no fuel came from it. That's a good sign right?
 

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Theoretically yes. Any smell of gas come out when you pulled the hose?
 

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Discussion Starter #5
No smell of gas in my opinion. Talked to a mechanic friend and he mentioned my idle control module/valve may be acting up. So I'll have him take a look at it and post what he finds or fixes for anyone else who is experiencing this problem. Probably going to change the camshaft solenoid actuator part that most people have problems with also. I have a feeling it will be missing a filter.
 

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Our idle/air control is controlled by the throttle body. No specific device like in other vehicles.

I don't recall what the process is on this truck, but you should check fuel pressure, or get it checked. Be sure the pump initializes to the recommended pressure (I do not not what that is). Also make sure it holds pressure. If pressure is bleeding off then something is wrong. I had a truck with a bad injector (held open). Obviously, in that case it didn't hold pressure as the fuel just dripped into the cylinder.

Probably the easiest way to start, get the pressure established.
 

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Throttle body cleaning may be in order also..?
 

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Discussion Starter #8
Our idle/air control is controlled by the throttle body. No specific device like in other vehicles.

I don't recall what the process is on this truck, but you should check fuel pressure, or get it checked. Be sure the pump initializes to the recommended pressure (I do not not what that is). Also make sure it holds pressure. If pressure is bleeding off then something is wrong. I had a truck with a bad injector (held open). Obviously, in that case it didn't hold pressure as the fuel just dripped into the cylinder.

Probably the easiest way to start, get the pressure established.
Thanks for the advice! I'll get on that.
 

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I just took care of something similar:
92k on truck, at a stop with or without air on, in park or neutral, the idle speed would drop from 650 rpm to 600 rpm (per dash tach). Seemed like it was missing just one beat. Could not pin down if there was one thing that I was doing to make this come or go. Usually the engine was warm but nothing else.
Cleaned the throttle body, cleaned the MAF sensor, sea foam in the gas. Nothing made it go away.
Bought new plugs, gapped to 0.040" - problem gone.
 

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Discussion Starter #10
My buddy put his tech2 on the truck and got 3 codes. One of which was something that had to do with the evap canister and solenoid located by the back right tire. Said I need to get a relocation kit to solve that problem. (First time hearing of this , sorry if I explained crazy.) he said over the years from the tire throwing dirt it will clog up and put strain on your engine.
The next thing was I replaced all my coil packs, but I'm still getting a misfire. So he recommended changing the plugs.

Can anyone shed some light on the relocation kit? I found a thread on just changing it for like 30$ on here. Thanks!
 

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My buddy put his tech2 on the truck and got 3 codes. One of which was something that had to do with the evap canister and solenoid located by the back right tire. Said I need to get a relocation kit to solve that problem. (First time hearing of this , sorry if I explained crazy.) he said over the years from the tire throwing dirt it will clog up and put strain on your engine.
The next thing was I replaced all my coil packs, but I'm still getting a misfire. So he recommended changing the plugs.

Can anyone shed some light on the relocation kit? I found a thread on just changing it for like 30$ on here. Thanks!
The code should tell you which of the 5 cylinders is misfiring.
Shoulda checked the plugs first before dropping the $$$ on 5 coils.
I suggest taking your truck to a mechanic.
 

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Have never heard of a "relocation kit" for the fresh air solenoid. It rests on a shelf near the spare tire. Mine set a code and I just replaced it. It may not cause a driveability concern.

Get your friend with the Tech2 to make sure your calibrations are 100% up to date (there were later software updates that addressed idle stuff).
 

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Discussion Starter #13
The code should tell you which of the 5 cylinders is misfiring.
Shoulda checked the plugs first before dropping the $$$ on 5 coils.
I suggest taking your truck to a mechanic.
It was a drawn out situation. I did change the spark plugs before getting new coil packs. Problem persisted and had misfires on 2 of the cylinders. Then another, so within 2 months I had them all replaced along with new plugs
 

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Discussion Starter #14
Have never heard of a "relocation kit" for the fresh air solenoid. It rests on a shelf near the spare tire. Mine set a code and I just replaced it. It may not cause a driveability concern.

Get your friend with the Tech2 to make sure your calibrations are 100% up to date (there were later software updates that addressed idle stuff).
Neither did I. I think it is pointless 200$ "fix" when you can just change the solenoid for roughly 30$. I will try that route in order to clear the code. He claimed it was in a bad spot from the making and it needed to be relocated. What exactly does the canister and solenoid do?

I will look into maybe some iridium plugs, and the ac delco solenoid part I found on another thread in here.Thanks for feedback
 

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If you get iridium plugs, don't gap them (you can damage the coating by bending the tip)

What plugs did you install last time?
 

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Discussion Starter #16
P0456 Evaporative Emission System Leak Detected (very small leak)
This doesn't seem like anything serious?
 

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Had the same problem I Pulled the TB completely off cleaned with the cleaner and old toothbrush changed the plugs as well as cleaned the MAF and it fixed my idle issue and helped my mpg by a few! Hope this helps
 
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