Misfire?

[wreedZ71]

Hey guys what does misfire feel or sound like?

[Zembonez]

Hey guys what does misfire feel or sound like?

Most of the time you won't feel or hear anything if it is a PO300 random misfire. Sometimes a single cylinder misfire is more obvious. It will feel like you are low on power and may be a slight shudder on acceleration. If it is constant, you'll be able to hear it in the exhaust as a dead spot.

[wreedZ71]

See my other thread: What do you think: http://www.gm-trucks.com/forums/index.php?showtopic=90595

[Zembonez]

See my other thread: What do you think: http://www.gm-trucks.com/forums/index.php?showtopic=90595

OK. First of all Dad isn't right about not being to drive it. Misfires can be very random or constant. Normally a missfire will trigger the CEL. What you describe sound less like a missfire and more like a fuel delivery problem. As I understand it the truck runs well after the initial stumble?

[wreedZ71]

BLANK....

[wreedZ71]

yes truck runs fine otherwise from 700 to 4000 rpm in all gears. It is only when coasting and you reapply the throttle to pass someone say around 55 mph. It will stumble once or twice then recover and be fine... I can reproduce this problem everytime so it isnt random I would say.

[Zembonez]

Pretty hard to call. Might have an air leak in the intake or air box... check and make sure all of that is secure. If you are not getting any codes, it's probably something that somebody will have to look at in person. Did this happen right after any changes in equipment?

 

I have heard of people running plugs other than OEM style had odd driveability issues. The proper plug is critical in these engines.

[wreedZ71]

I have had Airraid intake system on the truck for 80k miles now...

 

No codes at all. I dont drive the vehicle but I maintain for Dad. I changed rotor, cap, and wires about a month ago, test drove and it was fine. Changed the plugs on Sat with ACDELCO Plats as recommended by everyone and I started noticing this issue. However I would think if it was a issue with plugs it would run like totat shit, but I dunno.

[dlstewart01]

I have had Airraid intake system on the truck for 80k miles now...

 

No codes at all. I dont drive the vehicle but I maintain for Dad. I changed rotor, cap, and wires about a month ago, test drove and it was fine. Changed the plugs on Sat with ACDELCO Plats as recommended by everyone and I started noticing this issue. However I would think if it was a issue with plugs it would run like totat shit, but I dunno.

 

I have learned over the years when something is wrong, it usually involves the last change you made to the truck.

 

Don

[wreedZ71]

I have had Airraid intake system on the truck for 80k miles now...

 

No codes at all. I dont drive the vehicle but I maintain for Dad. I changed rotor, cap, and wires about a month ago, test drove and it was fine. Changed the plugs on Sat with ACDELCO Plats as recommended by everyone and I started noticing this issue. However I would think if it was a issue with plugs it would run like totat shit, but I dunno.

 

I have learned over the years when something is wrong, it usually involves the last change you made to the truck.

 

Don

 

 

 

Ya that is what everyone is telling me. **** I was actually hopeing it was something else! I guess I will take those plugs out..

[Zembonez]

I have had Airraid intake system on the truck for 80k miles now...

 

No codes at all. I dont drive the vehicle but I maintain for Dad. I changed rotor, cap, and wires about a month ago, test drove and it was fine. Changed the plugs on Sat with ACDELCO Plats as recommended by everyone and I started noticing this issue. However I would think if it was a issue with plugs it would run like totat shit, but I dunno.

 

Not necessarily. You may have gotten a bad plug. It's really hard to know here... One sure fire way to know is to put the old plugs back in and see if the problem goes away. I know that's a pain but if the problem started after the plug swap, that is where I would start.

 

Good luck with it.

[Zembonez]

All it would take is for some warehouse parts employee to drop the box of plugs on a concrete floor and crack the porcelain in one or more of the plugs for them cause a problem. Plugs need to be perfect, indexed, and gapped correctly to work right. Very critical item considering the combustion of every cylinder depends on them.

[wreedZ71]

I noticed in my Ford when i let of gas and hit brake and re applied throttle the TC would be unlocked, if I did not hit brake when I reapplied throttle the TC was still locked.

 

Is this the same operation as the Chevy should be?

[wreedZ71]

just pulled codes and none showed up.

[wreedZ71]

Well I just drove it 20 miles and guess what. I opened the hood and can see sparks on number 1 cylinder next to spark plug and boot I believe. Is this the cable or a bad plug? Cables are brand new. I did hear a popping noise on this particular plug when I loosened it alittle bit after installing.