2003 4.2 V6 GMC Envoy misfire Diagnose and Repair

The 4.2 had a terrible miss that happened out of the blue. In this video I diagnosed the misfire without using a reader just with basic tools. I changed out all the spark plugs anyway just due tothe fact no one knew the last time they had been changed. The issue turned out to be a bad coil pack winch usually costs around $50.00 from your local auto parts.

[@CAPHOTO1961]

Thanks for the video. I replaced all the coil packs with aftermarket, and put new spark plugs in, and turns out one wasnt sitting right. This video helped me sort out the problem. Ive got an 02 Envoy with 177k and she's running like a charm again. Its a good body design that stays in style. It still looks like new, and looks better than some of these over teched out 2023 models.

[@terencescott3957]

My 4th coil pack from the front was bad also. I figured it's been 19 years so I changed them all out. It only cost me $72. Purring like a kitten at 240,000 miles.

[@gtols228]

Best time saving video to date thanks

[@catfishredneck88]

bought a really nice clean 02 last fall. just took a 300 mile trip to missouri yesterday. ran perfect. today hooked up the pontoon to go fishing. soon as i pulled out shudders. it was my #2 from the front. no pops no rpm change. the rest did both. ruined the day but easy enough to fix.

[@flashesofblack4128]

That is not a v-6. It is an inline six.

[@dboy6400]

Sometimes called that to represent "Vortec 6", whatever that is. It was a marketing term years ago. Confusing though.

[@flashesofblack4128]

@@dboy6400 I agree. Its maybe just a marketing tool to make the bland old straight 6 sound real attractive. Those old engines have been around for decades and for the most part were pushrod engines.

[@kepler240]

that's a funny looking V6. almost looks straight

[@TG-LGreen]

Thats a 4200 atlas i6

[@jamesybarra7947]

The problem w aftermarket ebay coils they don't last so dont buy them . But the Delphi Coils (factory)are good but the spring in the rubber boot shrinks doesn't let spark run thru it so it fails just buy the replacement boots from auto part store don't buy the coil there still good.

[@TheChiefJudgeDredd]

Always check the basics

[@blackout260112]

What can cause low compression on 1 cylinder??? Had a misfire on 4, replaced the plugs , replaced coil packs, vvt and cam sensor, still run just like that... Help pleaae

[@shalvajulukhadze5816]

if the coils and sparks are new what else can detonate engine on cold ?

[@3434abab]

nice work! you should do voice overs btw.

[@ryanwinters4678]

I have 05 envoy gages stop! And yes it shacks and misses and surges!

[@scoutmaddoxg]

Why would this happen right after replacing fuel filter?

[@fishfire_2999]

Changed all plugs and coil packs #4 not getting fuel ?

[@MainyerdMax]

Injector I believe

[@mrjerusalem5513]

Did you replace the spark plug ??

[@valeriesarchett1804]

What are you listening for when checking which cylinder isn’t firing?

[@catfishredneck88]

when you pull each coil out individually you should hear the snapping of the spark as well as the engine should struggle to idle even more and go back to the slight miss when you put it back on. the one thats bad wont pop from the spark and the engine will ide the same. thats the bad one.

[@spiral187]

I have. A2004 Chevy ext 4.2 the hose that was on top that goes down to the left side can u tell me what it 8s mine 8s all broke

[@michaelmaker8169]

I just replaced starter, alternator. But when I connected The battery the headlight washer fluid sprayed me.
Funky electrical... Any idea why?

[@adamaleman5915]

Around how much price wise

[@Operator_WhiteKnight]

Its like 60 or 70 bucks on Amazon for six coils

[@terencescott3957]

I have a 2003 also. Just yesterday I changed out my spark plugs and all coil paks. It was running extremely rough above 50mph and the idle wasn't the same. You could tell something was going on. Well it's back to running smooth. Some of my gauges are broke also. The gas and temp work. And the battery is hit and miss. I bought stepper motors over 7 years ago and have yet to put them in. Maybe one of these days i'll get around to it. :)

[@stevestevenson289]

U hope mines the same, or plug even better

[@432b86ed]

I've got a '02 Envoy. Check your power steering steel pipes for rusted out holes where the lines run on top of the driver's side frame horn. You can access them from the fender well. I fixed mine, bion, with steel braided toilet connection hose and a two hoe clamps on each end - 5 years ago. no leaks or problems whatsoever. Before I refined my method here, I ran the pump dry a number of times. Those pumps can take a beating.

[@nathanz3511]

My 2005 gmc envoy 110,000 had a missfire I bought 6new spark plugs started running a little better except the coils were bad so I went to go buy 2 coils as I was changing them with the car on the car turned off. Had to have the car towed and now it’s cranking but won’t start. Anybody have any idea?

[@EntropiaPR]

Same here

[@may03LT]

yikes i hate my 2007 envoy the cd player doesn't work so i dont know what to think now my mechanic thinks constrruct bad or something im scared

[@OG_INC]

Please say “EA SPORTS ITS IN THE GAME”

[@josearioscardona4619]

2004 GMC Envoy SLt air condition not returning of

[@regionvoices5228]

Nice job Can you get knocked on your ass from touching the coil packs?

[@Thumper68]

I guess you could doesn’t to me.

[@pauldabey2873]

So you think you have a V6.
Funny.

[@matthewmatt426]

That not a V6 it's a st8

[@firehawk6911]

😂