I've got a 1990 2.3L with the factory 2BBL on it. For the past few months, it's been idling very rough and almost stalling after a cold start. I've been holding it at about 2k rpm for 10-20 seconds after a cold start, which has been fixing the issue.
Just this past week, the issue has either gotten worse, or another issue has appeared. Holding the gas for a bit makes it idle okay, but when I try to take off, it will shudder and (it sounds like) miss. If I'm easy on the gas, it'll run decently, but if I give it more than about 1/3 throttle, it will miss and shake and not do much. It will do this for a few minutes, and stop shortly after the engine reaches it's normal operating temperature.
I did some Googling and found the choke control solenoid can go bad, but I was wondering if anyone else might have any other ideas of what could cause this.
I replaced the fuel pump about a month ago, and it had no impact on the cold start issue. My carb also looks spotless from what I can see removing the air cleaner. I ran a bunch of carb cleaner through it today just to try to eliminate that, and it did not change anything.
I did notice when I pull the throttle linkage with the motor shut off, the second barrel did not open. This is normal, as it requires vaccuum, correct?
1990 Isuzu Pickup 5 speed 2WD - All factory, 110k miles