Sputtering Backfire - Chevy S10 With A Blazer 4.3 V6 Engine


Asked by Aug 09, 2016 at 10:52 AM about the 2002 Chevrolet Blazer 2 Door LS

Question type: Maintenance & Repair

Hi guys, I have a 1994 Chevy S10 that has a 2002 Blazer 4.3 V6 vortex
Engine in it. This morning on the way to work as I was going up an on-ramp
(uphill) to get on the highway, the truck began to sputter and seemed like it
was having a lack of power. Once on the highway there was a significant
change in the power and it began to sputter (especially in the first few
gears). While on the highway the engine light (which is always on probably
due to the fact that they put a different engine in the truck and it didn’t all
line up), started to flash. Then it went back solid again. Once I got off the
exit and was stopped at the red light, it began sputtering again and then
backfired slightly a few times. I made my way to my destination with
sputtering and a few small backfires (in the first few gears). Seems to have
the most trouble when stopped at light in drive idling and first few gears.
Then will drive fine but you can tell that it doesn’t have the same power.

I then took the truck to a gas station filled it up with premium (it was at
about ¼ of a tank before). Let it idle for 10-15 minutes and went to work.
Along the way same thing. Most of the sputtering and small backfire
sounds came mostly when stopped at light and going first few gears.

Note: there was some heavy rain yesterday and the truck is a bit low. I did
go through a few puddles yesterday on the way to work in the am. Never
noticed any changes after the puddles (about 10-15 minutes to my work). It
sat all day at work drove home just fine yesterday. No issues. Sat all night
then this morning drove it for 2-5 minutes before getting on the highway
and noticing the sputtering.

I checked the air filter and it is completely dry along with the inside of the
air filter container. My friend said it might be something to do with the wiring
and I might be able to see a spark if one of the wires is loose or not
connected properly. Not sure.

Any help would be greatly appreciated. Thank you!

7 Answers


Here are the error codes:


Here are the codes after I cleared them.


This is the part they said to replace first


Why cant i see the codes or what part ? i have the exact same problem !!


Ended up fixing it with new spark plugs, distributor cap & rotor.


Didnt help mine . I have also tried two different MAP sensors , two different MAF sensors , tried a different ignition module , coil and just tried a different EGR valve @3am this morning after looking for arcing from the new plug wires . (Yes , it has been keeping me awake at night).


Thanks to youtube , I am gonna check the distributor shaft for excessive movement , next , then if that seems fine , i'm saying its #5 injector . When it COULD be driven , autozone scan said O2 sensor (cat has been removed) and cyl. 5 misfire twice . This is bull !! My 1997 Blazer was fixed with a used MAF sensor . I read that the 2000 Blazer is the most problematic of all years . Ain't I the lucky one .

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