Would Bars Engine Repair fix a misfire?

Joined
Apr 15, 2017
Messages
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Location
Napa, CA.
I've posted before about my 2001 Chevy 5.3 with 292K on the clock misfiring above about ~4000rpm but running fine otherwise.

I tried changing the coil, wires, plugs, injectors, etc. It got a little better but didn't completely fix the problem.

Members here suspected it was a mechanical problem like lifter/cam or valve springs.

However, I've been driving the truck every day instead of my other vehicle for over a month now. I've driven several thousand miles... I drive a lot! Anyway, it used about half a quart of oil every 1500-2k miles based on my casual observation of the dipstick. So I added some Bars Engine Repair to the oil.

Anyway, yesterday and today I was really pushing the truck hard up a few long hills at high speed, well into the 5k rpm range, and there was no misfire. Before, the misfire was very consistent, it would happen every single time I pushed it that hard. I added that Bars stuff like a week ago, and until now I haven't gone above 4k rpm because I hardly ever need to.

Could the Bars Engine Repair really have solved the problem? I have been running Valvoline Maxlife 10w-30 oil. Looking forward to hearing your theories or thoughts on this!
 
I think your constant driving it (hard) cleared something out, akin to the old "Italian Tune Up."

Bar's Engine repair looks like good old VII like STP or Lucas. Mighta done something!
 
A high speed misfire should eventually cause the money light to come on. Is the CEL on? Have you pulled codes? Checked the misfire count with a scan tool? How about a compression test, or better yet a leak down test? Fuel pressure and flow rate? Short and long term fuel trim values? So many things that could be causing your issue...

I really doubt that Bar's Engine Restore would cause a high speed miss to clear up.
 
What about the infamous EVAP valve over the gas tanks front top outer edge small black plastic box the size of your hand . I've been dealing with the p300 and occasionally a couple of the 400 series codes on mine for 6 years,Showing the evap valve is faulty, or gas cap. Ya right that was the first thing I tried 🤬. My truck runs great, always has but it's a timing game to sneak it past inspection even with the help of a friendly mechanic who does all he can to get his customers in and out cheap..
I've had that $-30 valve sitting on a shelf for 6 years because it's such an 🙈 PITA to replace in mine . I have to remove the box to get at it . Supposedly you can reach and do them without having to do that. It's also , as I discovered watching this video a cause of random multiple misfire which just can't be cured. . So with that in mind , especially at your trucks age, you might want to give this a shot. Notice also how the video mentions this has been a real headache and for those early years in particular . Dust, dirt plugging it up. They even redesigned it just for that reason.
One thing I can't do is tell you is if this cured my RMM issues. The truck is down for a bit giving it new shocks and a 🤢 custom 🤦ðŸ»â€â™‚ï¸ Fit muffler to replace the 6 YO custom rig I welded on in 2014. Time for a refit of the old beater . Here's the link to that video, give it a look. Don't fear yanking the box if necessary, It's easy with an air gun, 6 18MM bolts and a couple of loom clips and it's free. 4 guy can lift it off easy enough but a tractor bucket and a couple of chains Is easier. Good luck. RMM codes is a real hassle on the GMs.

https://youtu.be/MFh9fCLzNbw
 
Originally Posted by Driz
What about the infamous EVAP valve over the gas tanks front top outer edge small black plastic box the size of your hand . I've been dealing with the p300 and occasionally a couple of the 400 series codes on mine for 6 years,Showing the evap valve is faulty, or gas cap. Ya right that was the first thing I tried 🤬. My truck runs great, always has but it's a timing game to sneak it past inspection even with the help of a friendly mechanic who does all he can to get his customers in and out cheap..
I've had that $-30 valve sitting on a shelf for 6 years because it's such an 🙈 PITA to replace in mine . I have to remove the box to get at it . Supposedly you can reach and do them without having to do that. It's also , as I discovered watching this video a cause of random multiple misfire which just can't be cured. . So with that in mind , especially at your trucks age, you might want to give this a shot. Notice also how the video mentions this has been a real headache and for those early years in particular . Dust, dirt plugging it up. They even redesigned it just for that reason.
One thing I can't do is tell you is if this cured my RMM issues. The truck is down for a bit giving it new shocks and a 🤢 custom 🤦ðŸ»â€â™‚ï¸ Fit muffler to replace the 6 YO custom rig I welded on in 2014. Time for a refit of the old beater . Here's the link to that video, give it a look. Don't fear yanking the box if necessary, It's easy with an air gun, 6 18MM bolts and a couple of loom clips and it's free. 4 guy can lift it off easy enough but a tractor bucket and a couple of chains Is easier. Good luck. RMM codes is a real hassle on the GMs.

https://youtu.be/MFh9fCLzNbw

Thank you, but I have no box, I have a burb. But I'll research it 🤗

PS: I see multiple parts in the evap system when I look it up in the computer. What part are you talking about? Thank you!
 
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