YACT: New plugs = hard start, rough cold idle??

[Ornery]

The Bosch plug has a tiny diameter electrode in the center, and I don't believe the ground electrode is platinum at all. One of them started missing on my car after only 8 months use!

 

[T2T III]

Originally posted by: Armitage

Yea,the wires look fine. I watched it running in the dark last night and didn't see any arcing & such, which I've heard can happen when they're on their last legs.

This isn't always the case. The resistance on a plug wire could also be bad causing the plug wire to not perform properly. This could happen well before the plug wire gets to the arcing stage.

With my vehicle, I changed the plugs a few months back. My vehicle still would hesitate a bit when hitting the accelerator. My plug wires never arced at all. My vehicle only has 58K on the odometer, but I just replaced the plug wires. All the hesitation issues have disappeared.

 

[Armitage]

Originally posted by: lightpants

Originally posted by: Armitage
I replaced the plugs in my Land Cruiser yesterday. Put in Bosch Platinums. This morning when I went out to start it, it started hard ... not real hard, but usually it's like nothing. The idle was also low & rough ... stalled twice on me, which it never does.

I just rechecked the Bosch site .... I have the right plugs & gapped correctly.

The only other stuff I've done on it recently:

- New aircleaner
- Cleaned battery terminals

I also had to take the pipe from the air cleaner to the throttle body off to get at one of the plugs. Shouldn't matter.

Any ideas?

Change out the POS Bosch Platinum plugs and it will fix your problem. I have seen this same problem many times before.
Did you disconnect the battery when you cleaned the battery terminals? If so, your car might have to relearn the idle settings. How many miles do you have on the car?
However, I would change those plugs asap.

I think we may have a winner here. I heard the same thing on a Landcruiser mailing list.
It ran fine going home last night, and no problem at all starting and idling this a.m.!
So for now, we'll see how the Bosch plugs hold up.

 

[funboy6942]

Bosch, champions (good only for your lawnmower), and auto lights are junk. You should always change your plug with what was in it. Only time you should change is if they do not make that plug anymore. If its a ford put motocraft back in, chevy-ac delco, if ie had ngk from the factory or has proven itself as a good plu stick that back in. I will bet my life that if like the others said you pull thoes out and put ngk back in your car will run smooth again.

 

[Armitage]

Originally posted by: moochadime
Bosch, champions (good only for your lawnmower), and auto lights are junk. You should always change your plug with what was in it. Only time you should change is if they do not make that plug anymore. If its a ford put motocraft back in, chevy-ac delco, if ie had ngk from the factory or has proven itself as a good plu stick that back in. I will bet my life that if like the others said you pull thoes out and put ngk back in your car will run smooth again.

Uhm, it is running smooth as silk again. I might disconnect the battery again just to test the theory ... but not until I figure out the stupid alarm issue 😛

I didn't know what plugs were in there originally, and the NAPA guy said that Bosch was the OEM. Turns out OEM is either NGK or Denso.