jdsmith46

So it has been some time since I have owned and SC. Got one this summer and trying to get it squared away.

My problem is the car had been fuel fouling all the plugs. I changed the cap, rotors, plug wires. I did find one of the coils had a crack down it and replaced both of them. Still fuel fouled the plugs. The cats got red hot and had to replace them as well.

I sent the computer out for rebuild, installed but after about 50 miles it fuel fouled again. I sent the computer back to them for them to check it out. They did rework the entire computer and just got it back- I sense they found something needing fixed.( before I sent off I checked the plugs and 6 of them were fuel fouled and 2 of them were right on point). I need to change the old plugs out and see what I have.

I will say I have not been able to set the TPS correctly. I would get a flat spot around 2500 rpm.

Anyway, is there anything else I am overlooking? the caps and rotors are new Bosch and the coil pack are aftermarket unknow maker.

Tallyhoe

Should probably acquire new spark plugs from an auto parts store, as Amazon is going the way of Ebay and selling counterfeit parts. So the issue may be the spark plugs themselves, other than that, maybe check for leaking fuel injectors. I had a similar issue with the cracked coil and cooking the cats so I swapped both coils out, problem solved. I keep the good coil in the trunk as a spare drivability is good as it's my daily right now.

jdsmith46

The coil packs are from amazon. I think I may just take those off to be safe

Tallyhoe

The Tundras forum calls it SCAmazon and Flebay

jdsmith46

So I put the rebuilt computer in with new NGK platinum plugs. Started up great and idle great. I took it for a 30 miles drive then back to pull plugs for a look. During my trip at 75mph constant speed I could feel a little flat spot, may be from TPS sensor adjust since I did remove before.

So my plugs are a telling tale. Plugs 1, 7 2, 8 are perfect. Plugs 3 and 5 are black carbon looking. Plugs 4 and 6 have very very mild black to them.

So on the distributor cap both plug wires are of course next to each other, both inner most part of cap. Anyone think its a cap/rotor issue or ECU issue? ECU on last rebuild had all the plugs smelling of raw fuel. That is definitely no more, just my two middle plugs with odd behavior. The plug wires are new, caps and rotors are too. They are bosh parts .

Could low coil output be a sign on the same 2 middle plugs or ecu?

Anyway any insight would be great.


Plug 3 and 5 look like this.


Plug 4 and 6 look like this

Tallyhoe

Maybe bad fuel?? I'd say try to drain the tank, but with gas prices nowadays, I'd say clean those sparks and try burning that fuel in the tank, or toss some seafoam in there, just observe the quantity needed depending on how much gas is in the tank, and then refill with shell premium.