Question about 2002 GMC Envoy

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2002 gmc envoy runs rough with flashing check engine light after sparkplug change and throttle body cleaning

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Posted on Jan 02, 2017

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SOURCE: i have a 2002 gmc envoy bringing up codes P0440

440 is Evaporative emission control system malfunction. Could be as simple as cleaning your gas cap & filler well & making sure gas cap is on tight, as that is the most common cause, otherwise you may need to check for vacuum leaks or purge solenoid has failed, or canister may be plugged.
495 is telling you that your engine/rad cooling fan, is malfunctioning as well, which I suspect is causing that noise your hearing. Have it looked at a.s.a.p. as it can do some real $$$ damage if it flies apart.
Have codes erased after fixing fan & making sure cap is tight, then see if 440 comes back, if it does, you may need to do more investigation.

Posted on Sep 03, 2009


SOURCE: change sparkplugs

go to mechanic

Posted on Oct 04, 2008

  • 31 Answers

SOURCE: replace starter on 2002 GMC Envoy SLT

check to see if the starter itself is getting a signal to crank. youll need to use a test light and have someone else try to start the vehicle, while you probe the wire to the starter to see if it is getting power. if not, check the starter fuse to make sure its not blown, as well as the starter relay to make sure that is good too (very common on gm's for bad relays) if the fuse and relay are good, but your not getting signal, it is an ignition switch problem.

Posted on Dec 11, 2008

  • 40 Answers

SOURCE: 2002 gmc envoy check engine and reduce engine

typical causes: dirty air filter, clogged up catalytic converter

Posted on Feb 23, 2010

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SOURCE: check engine light....coolant temperature sensor

take altanator off and it is located right behind

Posted on May 25, 2010

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1 Answer

Engine Runs Rough

It could possibly be dirty injectors. Try a good injector cleaner, I've had good luck with sea foam bra

Aug 02, 2014 | 2002 GMC Envoy

1 Answer

The Reduced engine power light is on. I have changed the Pedal position sensor and I have removed and cleaned the Throttle body. What next?

Did you also have a "check engine" or "service engine soon" light? If so, did you have a scanner "read" the error code and record what code was set? It sounds like a throttle body problem, but the OBD code will narrow it down.

Oct 01, 2013 | 2002 GMC Envoy

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02 gmc envoy running rough after disconnecting battery to fix headlight. The truck ran perfect ! I disconnected the battery to replace a new headlight wire and when i plugged the negative line to the

You need to have the throttle body cleaned. On this engine it gets gummed up. Make sure that both front and back sides are cleaned thoroughly.

Apr 08, 2013 | 2002 GMC Envoy

1 Answer

Changed spark plugs on 2003 gmc envoy 4.2lno runs bad

First of all, did you use AC Delco Iridium plugs part number 41-103? These are the best plugs for this engine.
Second, did you firmly seat the coil pack when reinstalling them on each plug?
If it is running bad, are you getting the Check Engine light coming on? If so, what is the code?
When you changed the plugs, did you disconnect the battery? If you did, the rough running could mean that the throttle body should be cleaned.

Nov 11, 2012 | 2003 GMC Envoy

1 Answer

2003 envoy smells like fumes and idles rough

have you checked for a vacuum leak?pcv attached,no leaks around plenum,engine coolant temp sensor reading right.

May 31, 2012 | 2003 GMC Envoy Xl

1 Answer

2002 envoy engine stumbling

Try cleaning the throttle body first. Make sure to clean both the front side and rear side thoroughly. Also, disconnect the battery while doing the cleaning, this will reset the computer and allow it to relearn to the cleaned throttle body.
Unless you have the check engine light on and can retrieve a fault code, do not start to change parts. With the mileage you have, you may want to change the O2 sensors.

Nov 13, 2011 | 2002 GMC Envoy

1 Answer

Reduce engine light came on in my 2002 envoy and it feel as if the truck is not getting any power, why is that? the truck slowed down so i pulled over cut it off an started it back up. after starting back...

Reduced engine power is just like a safe mode. First things first, clean your throttle body. It's possible the butterfly is sticking. Disconnect the battery, clean your throttle body with throttle body cleaner, must be nice and shiny. When finished, drive around for 20 minutes or so with all accessories off. This will allow the computer to relearn a properly functioning throttle body.

Mar 25, 2011 | 2002 GMC Envoy

1 Answer

Recently i replaced battery in my 2002 envoy, now if a/c is on it idles rough and will stall, can you help me with solving this problem

Clean your throttle body. Disconnect the battery, and take the plastic resonator and large hoses off that attach to the throttle body. Clean with throttle body cleaner, must be nice and shiny. When finished, drive around for 20 min or so, so the computer can re-learn the properly functioning throttle body. Your computer learned some bad habits with the dirty throttle body, so when you disconnect the battery and reconnect it, it thinks the throttle body is clean and functioning properly which is not the case. If you do it yourself, can cost you a can of throttle body cleaner $7.

Feb 19, 2011 | 2002 GMC Envoy

1 Answer

2002 GMC envoy slt 4.2 v6 My question is.. I recently changed the water pump on my wife's envoy. After replacing it the car idles low and high, low and high constantly. No normal idle like before. I...

Sounds like you may have disconnected the battery. Does the rough idle only happen when the defroster or A/C is on? If so clean your throttle body with throttle body cleaner with the battery disconnected. When finished, drive it for 5 or so miles with the defroster / AC off to let the computer relearn the settings. This will solve your problem.

Dec 21, 2010 | 2002 GMC Envoy

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