Progress Thread Komo's 1990 GT - Parts Gathering Purgatory & Home Remodel

gkomo · May 19, 2026

Well, chalk up another issue.

When i started my car this morning and was just driving slowly through the neighborhood to get to the freeway i noticed the AFR seemed way more rich than it normally does. Like in the high 12's to mid 13's. Typically i've yet to have any issues with AFR, always showing in the sweet spot of high 14's. So i was monitoring the gauge all the way to work. Well, as i'm just cruising along on the freeway, gauge just goes "- - - - -". Then when i downshifted to get off the freeway it was like in the 20's. Then, getting closer to work it goes back to somewhat 'normal' except is showing more lean than typical, like in the 15's even into the 16's. Mind you this is all just low RPM driving normal.

Idling at a stop light my vacuum was at 17ish which i think is normal for my car.

Wonder if the sensor is going bad already, or a vacuum leak somewhere? Although car seemed to run fine so i don't think its a leak. I'll check my ground for the gauge to make sure it hasn't come loose. I'll try to peak under the car to see if the wiring looks okay there too. I basically just zip tied the wiring out of the way of the exhaust temporarily.

Noobz347 · May 19, 2026

That appears like an interruption in power going to the sensor or an interruption in communication between the meter and the sensor.

If I am correct then seeing it lean after recovery isn't so strange. Do a free air calibration. The last one was unplanned if I am correct, above.

gkomo · May 19, 2026

Something interesting to note. I just swapped out my troublesome #7 plug (my weekly ritual) and noticed the ground side electrode is more brown than normal. Typically, with how this cylinder is, the entire plug is just straight black with oil. You can see the oil on the plug threads, but usually the central electrode and ground side electrode are just as black as you could imagine. Now, this is the first time i'm seeing some brown and not oilyness to the plug tip.

Only thing i've changed is the coil.

I also checked my AFR gauge power and ground connections (visually) and see nothing amiss. Maybe with this cylinder issue i'm having, and leaking/burning oil inside the combustion chamber i could have just fouled the sensor?

Noobz347 · May 19, 2026

I don't see anything remarkable on that plug. It looks like it should look if the cylinder is getting some oil.

You still tracking down the source? Is there any in the throttle body or upper plenum?

gkomo · May 19, 2026

Noobz347 said:
I don't see anything remarkable on that plug. It looks like it should look if the cylinder is getting some oil.

You still tracking down the source? Is there any in the throttle body or upper plenum?

Thats sort of what worries me. The plug has always looked like hot garbage when i swap them out, so what made it look somewhat normal this time around? I guess its like a good worry, but still just confused to what changed.

I'm starting to think its less the piston rings (my original assumption) and more valve stem seals leaking specifically for this cylinder. All other plugs look normal when i've checked. Its just this one cylinder.

When i removed the upper to get the injectors cleaned, the inside of the manifold was caaaaaked with sludge. I've since replaced the PCV components and i have the added supercharger 'breather' (if you want to call it that) line with the inline filter... which has caught some oil vapors near the airbox. I have another PCV mesh and valve I will swap again once back home.

But to answer your question i have not recently checked the TB or upper plenum. I will be removing all that again to put 24lb injectors in hopefully this fall.

Noobz347 · May 19, 2026

gkomo said:
Thats sort of what worries me. The plug has always looked like hot garbage when i swap them out, so what made it look somewhat normal this time around? I guess its like a good worry, but still just confused to what changed.

My guess? It's new and it's firing.

Yeah, look and see if you can track down the earliest point in the inlet tract where you see oil.

Does your "breather" have a check valve? If not, your PCV system isn't doing much.

gkomo · May 19, 2026

, i think i may know my issue with the AFR gauge. Like you said, could be power related.

Went to drive the car to O'reilly's to pick something up for my 4runner and sitting at a light the RPMs dipped pretty low. It didn't die but thats unusual. My cluster voltmeter gauge was at the bottom (normally at the 3/4 range) and my battery light came on. So, i quickly turned around to head back to work. The voltmeter gauge came to life briefly on the way back before going dead again.

Now i need to figure out how i'm gonna get home...

gkomo · May 19, 2026

With a Fluke we have at work, battery was at 12.4v, car on it was only at 11.78v so i think my alternator kicked the bucket.

gkomo · May 19, 2026

Are any of these alternators any good? I was thinking either the ACDelco or the Bosch reman units:

gkomo · May 19, 2026

Noobz347 said:
My guess? It's new and it's firing.

Yeah, look and see if you can track down the earliest point in the inlet tract where you see oil.

Does your "breather" have a check valve? If not, your PCV system isn't doing much.

The 'new' supercharger breather setup does not have a check valve. I just installed it as per the instructions.

I will pick up the same UPR check valve i put in my PCV line and add it to the other supercharger line.

I'm thinking i'm just gonna have the car towed to my house and let it sit on the street until we move back in. Too many issues, not enough time.

gkomo · May 19, 2026

Well, i ordered the new Bosch alternator from RockAuto. Gonna have AAA tow the car to the house and i'll get to it when i get to it. Looks like the Stang won't be driven for a while now.

nicholase · May 19, 2026

That all sucks. Alt should be an easy fix though.

gkomo · May 19, 2026

nicholase said:
That all sucks. Alt should be an easy fix though.

It will be easy for sure. Glad I reversed the one alternator bolt when installing the supercharger. Now I shouldn’t have to take the whole bracket off.

Just need the wife to watch both kids one weekend time so I can knock this out.

91AOD5.0LX · May 19, 2026

gkomo said:
Looks like the Stang won't be driven for a while now.

Sorry to hear this. We Have all been there. You will square it away sooner than later.

gkomo · May 20, 2026

Well, here we go again:

And to the left is the building that recent San Diego shooting was at... right near my work. Actually when i left work the day of i left early and was trying to get on the freeway right there and there were roughly 75+ cop cars all around this area:

And her final resting place until hopefully September (house in background). Disconnected the battery, locked and covered her up. I wanted to park in front of the storage unit (in front of my house) but my neighbors car was parked there. Hopefully my other neighbor doesn't get mad the cars in front of her house now. She's an awesome older lady:

Noobz347 · May 20, 2026

gkomo said:
Well, here we go again:

Like I need another excuse to look at Tawney Kitaen from the 80's.

View: https://www.youtube.com/watch?v=WyF8RHM1OCg

gkomo · May 22, 2026

Is TRE Performance a reputable site? They have the Harland Sharp TW specific Roller Rockers on sale compared to just ordering through Harland Sharp. I'm looking at the S4303 set (1.7 7/16 stud), $473 from Harland Sharp, $415 from TRE.

Nevermind, Summit has them for the same price as TRE... probably just order through Summit.

AeroCoupe · May 22, 2026

For the most part TRE has good reviews but their return policies are pretty harsh. Summit has way better service in that arena.

gkomo · May 22, 2026

Alright ordered the:

- Harland Sharp S4303 1.7 RRs
- FMS-M-6500-R302H lifters

RADIO was the only Summit coupon code i could find, which is only $10 off. Puts a non existent dent in the $800+ order haha

AeroCoupe · May 22, 2026

Pays for their “handling” charge….

Progress Thread Komo's 1990 GT - Parts Gathering Purgatory & Home Remodel

now i can hopefully expect to receive the shaft

Stangnet Facilities Maint Tech... Er... Janitor

now i can hopefully expect to receive the shaft

Stangnet Facilities Maint Tech... Er... Janitor

now i can hopefully expect to receive the shaft

Stangnet Facilities Maint Tech... Er... Janitor

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

I lubed and pushed, until it was all the way in

now i can hopefully expect to receive the shaft

I have a slight sag in my rear

now i can hopefully expect to receive the shaft

Stangnet Facilities Maint Tech... Er... Janitor

now i can hopefully expect to receive the shaft

lube between the nut and the face. I know my lubes

now i can hopefully expect to receive the shaft

lube between the nut and the face. I know my lubes

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