Rich condition and misfires

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Aug 11, 2022 | 04:21 PM

#71

GeorgeLG

BF Veteran

Joined: Jan 2007

Posts: 4,628

From: Florida

Proper diagnosis, $20 and no parts cannon! This makes me smile, congratulations.

Besides getting you fixed up now I completely understand the evap purge valve operation.

Good work,

George

Aug 11, 2022 | 04:33 PM

#72

GeorgeLG

BF Veteran

Joined: Jan 2007

Posts: 4,628

From: Florida

I think that there’s two ways that the charcoal canister can become so saturated that it affects the running of the vehicle. The first is over filling the gas tank which we’ve discussed. The second would be a poorly functioning purge operation due to the purge valve not opening completely, restrictions in the lines, restrictions in the canister, the vent solenoid, etc. I have experienced the overfilled gas tank problem but not my second theory. After seeing how aggressively the system purges at highway speed‘s I’m thinking that overtime a compromise pursed circuit might also cause this problem.

George

Aug 13, 2022 | 01:33 PM

#73

GeorgeLG

BF Veteran

Joined: Jan 2007

Posts: 4,628

From: Florida

I updated post #69 where I summarized purge valve operation after a three hour highway cruise. That concludes my purge valve measurements.

George

Oct 8, 2025 | 11:08 AM

#74

Eric990

New Member

Joined: Oct 2025

Posts: 5

Got a very similar problem!

Quote:

Originally Posted by GeorgeLG

So now we know that you have either a failed closed evap vent solenoid, a plugged charcoal canister and or plugged lines. The canister may be soaked in fuel and/or there may be a leak at the tank/cap. Normally when the purge valve opens it pulls fresh air into the vent solenoid and through the canister. I bet we are getting mostly gasoline vapors. Disconnect the vent solenoid from its tubing remove the gas cap and tape the fill opening and let’s see what we get.

George

hey thank you two for the deep dive I have a very puzzling. Similar issue. Wondering if I could ask you a couple questions on how yours ran. Thanks!

Oct 8, 2025 | 11:12 AM

#75

DannyTheVito

Thread Starter

New Member

Joined: Feb 2018

Posts: 67

From: Ontario

Quote:

Originally Posted by Eric990

hey thank you two for the deep dive I have a very puzzling. Similar issue. Wondering if I could ask you a couple questions on how yours ran. Thanks!

Hey Eric, dunno the preferred method on this forum, but might be best to open a new thread describing your issue. Probably get more eyes on it that way and I'd be happy to help with troubleshooting. I've gotten quite familiar with these Blazers over the last 9 years of owning them lol.

Oct 8, 2025 | 11:19 AM

#76

Eric990

New Member

Joined: Oct 2025

Posts: 5

Quote:

Originally Posted by DannyTheVito

lol I get it! Yours acted up the most during the warm up fade correct? Mine runs like a too cold. Around 6 minutes drive time it stutters hard. Rpm’s all over
the place. Never shows a miss fire though. Will die at a stop light. Then runs fine again after about 8 minutes of running terribly.

Oct 8, 2025 | 11:36 AM

#77

DannyTheVito

Thread Starter

New Member

Joined: Feb 2018

Posts: 67

From: Ontario

Quote:

Originally Posted by Eric990

Got access to live data? I just use a little ELM bluetooth dongle off amazon and Torque Pro on my phone. Super invaluable.

Mine bogged down really hard after driving for a while. After replacing the filter media in the charcoal canister that was resolved, but I still had other issue that I am actually still troubleshooting. I just got done replacing the cylinder heads last week because #3 exhaust valve was getting stuck open on heavy pulls. Thank god for non-interference engines.