So my 91 3.1 Red Dragon finally let me down and abandoned my wife and after taking her out for lunch. She would fire, but not keep running. Had to have her towed home. She started fine the next morning and I took her to work. On the way home, she died after a couple miles and would restart momentarily, drive a few hundred feet and die again (towed home again). After suspecting bad injectors, I tested the resistance and sure enough, 2 of 6 had 0 ohms when hot, 2 were at about 6-8 and 2 were around 11. I replaced them all, but as luck would have it, I also broke several of the of those hard brittle vacuum lines, so I replaced all of them (therefore pretty sure there's no leaks anymore if there ever were). Fuel pressure is about 42 though it does droop to about 39 if I do a hard acceleration and quickly recover to 42. Additionally, I noted significant corrosion inside the distributor, therefore replaced it and the rotor, too. Finally, after replacing the fuel injectors, I noted my EGR had a snapped bolt, causing blow-by of exhaust into the engine compartment, so I fixed that, too. After all that, I disconnected the battery to reset the computer (after verifying there were no codes present (never were any)).

So, now, it starts right off, but it bogs down on initial acceleration and when coming to a stop, it almost dies (RPM down to about 400) before it fires up again (today it did die completely once). It runs like this for about the first 15 minutes and then smooths out nicely. However, another thing I've now noted is that it now doesn't want to upshift sometimes. It will simply stay in first gear until about 3000 RPM and only shifts up when I relax pressure on the throttle or pump it gently. When it does shift, it does so with a bit of a surge (probably because of the higher RPM than it should have. The shifting issue occurs regardless of temperature.

Any ideas out there?

 

Only the obvious of did you replace the fuel filter and tranny filter and service it? My S-10 was shifting hard like that, and I serviced the tranny and put a bottle of Lucas Transmission Fix in it and it fixed the problem there.

 

Haven't done a tranny filter replacement just now, but did so just a few thousand miles ago. Didn't think anything of the fuel filter replacment as the fuel pressure seems ok.