Plug gapping

Hi all,

I'm a very old guy with a 1999 2.7 4WD. It has been a wonderful truck, much beloved. Now it will begin to start but misses so badly it won't stay running longer than three or four seconds. It feels like it is firing on but one cylinder. Following advice found on this forum, I ordered four Denso Iridium TT Spark Plug 4701 and new NGK Wireset 4441 plug wires. I haven't received the wires yet and haven't replaced but one plug.

The electrodes in these new plugs are different from any I've encountered before, being much pointier. The gap in the new ones from the box was consistently .036. My manual indicates the gap should be .031. The plugs I removed (same pointier electrodes) were gapped greater than .040. My question is: does the manual tell me .031 because they assume ordinary electrodes and I should have left them as they came from the box - or was I right to reduce the gaps to .031? I thought maybe Denso gapped them just in between the 4Cyl specs (.031) and the 6 Cyl ones (.043).

Any recommendations? Thanks so much for any help.

Clive

 

A gap specification is a specification. Set it to your truck.

Plugs may come gapped consistently but that doesn't mean they are correct for your application.

 

Welcome aboard

 

From one old guy to another. I stick with the OEM plugs.

 

Welcome to TW

 

the 6cly doesn't use iridium plugs so they wouldn't be gapped to 6 cyl specs, either way plugs are never really gapped consistently

 

Thanks for the welcomes you guys, and thanks for the time and thought.

Mine is FOUR cylinders, 2.7L. (The engine sticker reads E3Rz-N73; my manual says it would be "3RZ-FE")

It seems the OEM's are "traditional" electrode types and the gap specifications (.031") would refer to that type of electrodes. Does anyone know if the specified gap for the ones I got (Denso Iridium TT Spark Plug 4701) would be larger than the manual specifies?

I could be negating the effect of the later-model, more expensive plugs, by setting the gap incorrectly.

Thanks again so much,

C

 

Welcome to TW!

 

Be careful gapping iridium plugs. They have a narrow fragile electrode.

 

Welcome!

 

Welcome to TW! You always need to check the gapping in plugs.

 

Welcome to TW! I would have to agree...stick with OME parts and always check the gap before installing. Wondering if there are other issues in play here...
Do you have access to a OBD2 scanner and if so....did it provide a fault code? if so what was the code....

Good Luck and keep us all posted...we will try to help as much as we can....