Have you tested the O2 sensors? Might even be cheap enough to just replace.

Plenty of diagnostics you can do...test fuel pressure, test O2 voltage, check vacuum at idle, pull the plugs and check for fouling, test for vac leaks, etc. Not sure if you can bench test those old TBI injectors bur st 175k they might be giving up too.

I did a quick skim of the thread, does this issue happen all the time or only cold/warm?

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

It happens warm or cold. I forgot to mention that I swapped in a 02 sensor a few days ago. Holy crap that was an ordeal. On top of everything else, I need to get it smogged to renew my tabs. I bought the sensor, I went to the mechanic for the smog, the same guy also smogs (from the verb “to smog“). He loaned me his Snap-on 22 mm to put it in on the street. Using both arms I could barely get the damn thing to move for about 3/4ths of the extraction. Putting the new one in only slightly easier. Somehow I emerged relatively unscathed. He told me that he’s seen them so badly seized that he had to cut the nipple out and weld in a new socket.

I had read that a bad O2 sensor would lead to hesitation issues. The new one had no effect, but I’m pretty sure the old one was aging out anyway. I am wondering about vacuum issues as well.

When I first saw the symptoms 2 to 3 weeks ago, I limped into an O’Reillys and put in plugs, cap and rotor, cables, and air filter in the parking lot. I always have a set of tools with me. The old plugs looked pretty bad, and it ran 90% better. It’s been a strange experience, hopefully I’ll get some valuable lessons from it.

I haven’t had the new plugs out for a looksee yet, I’m thinking to take one or two out later today.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K