Engine jittering while flooring it after installing Densos High performance spark plugs

[tumtum]

I just installed the new densos high performance spark plugs off the jb4 website so that I can install the JB4 chip. But after I installed it under full throttle my engine sort of jitters. I don't think it is the transmission either but who knows? I have the 3.3t. I don't know if it could be engine knock, misfire, or what? Did anyone else have this problem. Also I may have just messed up the installation of the plugs because I did it myself.

 

[Toddasaurus]

Did you end up gapping them at all? Any pics?

Make sure the coil packs are fully seated.

I doubt it's the tranny. My bet is on the plugs. There have been reports, both here and on the Stinger forum, of Denso's having some poor quality control. This might be what's causing that weird sensation you're getting at WOT. My assumption is that the plugs are misfiring at high RPM's.

 

[tumtum]

Yea I gapped then to .022 and no I don't not have any pics unfortunately. A buddy told me that it might be bad gas, but I also didn't tell him I changed the spark plugs. I might wait a few days to see if my car will get used to them or not, should I just buy new plugs and have a shop do install them correctly?

Did you end up gapping them at all? Any pics?

Make sure the coil packs are fully seated.

I doubt it's the tranny. My bet is on the plugs. There have been reports, both here and on the Stinger forum, of Denso's having some poor quality control. This might be what's causing that weird sensation you're getting at WOT. My assumption is that the plugs are misfiring at high RPM's.

 

[Toddasaurus]

Yea I gapped then to .022 and no I don't not have any pics unfortunately. A buddy told me that it might be bad gas, but I also didn't tell him I changed the spark plugs. I might wait a few days to see if my car will get used to them or not, should I just buy new plugs and have a shop do install them correctly?

Double check your coil packs, also I think it would be a good idea to pull the plugs and inspect them, double check your gap, and make sure the center and ground electrodes look good. There is a chance that you've just got plugs that happened to be crappy quality. Usually Denso's work great, but you're not the first person to have problems with them despite doing things correctly.

Personally, I prefer re-gapped OEM plugs. Been running mine for approx 3,000 miles, with upgrades, and they've been perfect.

 

[socrbob]

Where did you get the gap spec? It sounds a little off to me?

 

[tumtum]

Where did you get the gap spec? It sounds a little off to me?

I got them off the jb4 website

 

[socrbob]

Thanks for your reply, just seemed a little too tight to me. Apparently the jb4 requires the smaller gap. Have you gotten rid of your problem, if so how?

 

[tumtum]

Thanks for your reply, just seemed a little too tight to me. Apparently the jb4 requires the smaller gap. Have you gotten rid of your problem, if so how?

No not yet I'm going to wait a few more days and if the problems persist I am going to go to a shop and ask them to check my work if I did everything right, but I'll keep you updated.

 

[socrbob]

Ok, good luck, hope it clears up.

 

[tumtum]

Double check your coil packs, also I think it would be a good idea to pull the plugs and inspect them, double check your gap, and make sure the center and ground electrodes look good. There is a chance that you've just got plugs that happened to be crappy quality. Usually Denso's work great, but you're not the first person to have problems with them despite doing things correctly.

Personally, I prefer re-gapped OEM plugs. Been running mine for approx 3,000 miles, with upgrades, and they've been perfect.

Did you regap the OEM plugs to .022?

 

[Toddasaurus]

Did you regap the OEM plugs to .022?

I regapped mine to 0.026. The factory gap is huge, at 0.035"

 

[tumtum]

I regapped mine to 0.026. The factory gap is huge, at 0.035"

Ok thanks, what did you base the .026 off of.

 

[tumtum]

Also I may have figured out my problem. I went to the mechanic shop and they said I had low counts of misfire in cylinder 2, so it probably happens under WOT. I order a new plug and I'll replace it and see what happens. Also when you anyone replaced their sparkplugs did their gas mileage go down?

Ok thanks, what did you base the .026 off of.

 

[Toddasaurus]

I can't remember how I got 0.026", but it seems to be working pretty good. Haha.

Unsure about my gas mileage. I haven't driven much highway recently so I can't really compare just yet..

 

[tumtum]

I just installed the new densos high performance spark plugs off the jb4 website so that I can install the JB4 chip. But after I installed it under full throttle my engine sort of jitters. I don't think it is the transmission either but who knows? I have the 3.3t. I don't know if it could be engine knock, misfire, or what? Did anyone else have this problem. Also I may have just messed up the installation of the plugs because I did it myself.

Hey guys I figured out the problem. One of my spark plugs were cracked. I probably cracked it in the installation because I dont know crap lol. But I installed a new plug and it seem to fix the problem. However I forgot to check if there was ceramic left at the bottom of the cylinder... o well we will see what happens

 

[Toddasaurus]

Oh dang! Yup, that's cracked lol.

If the engine is running smoothly now then I think you're all set. If there was ceramic in the cylinder then you would've noticed something weird upon startup.

I'm glad you got it taken care of!!

 

[Wyo_Cowboy]

Glad you were able to fix @tumtum. It's no fun taking the intake off to get to the passenger side plugs.

 

[tumtum]

Glad you were able to fix @tumtum. It's no fun taking the intake off to get to the passenger side plugs.

Funny thing tho, we couldn't take the intake manifold off completely, because the clamps attached to the intake had bolts I've never seen before so we managed to take out the sparkplugs with out taking off the intake. It was much harder tho and a lot slower. I'll provide a picture of the bolts I'm talking about later.

 

[Wyo_Cowboy]

Funny thing tho, we couldn't take the intake manifold off completely, because the clamps attached to the intake had bolts I've never seen before so we managed to take out the sparkplugs with out taking off the intake. It was much harder tho and a lot slower. I'll provide a picture of the bolts I'm talking about later.

Those are just caps over the clamp screws on throttle body. Just pop off.

 

[tumtum]

Those are just caps over the clamp screws on throttle body. Just pop off.

O damn if I knew that it would have saved me so much headache.