i have a base model 1990 civic hatchback with the original Throttle Body Injected 1.5L engine and 4speed manual transmission. it starts first try every time, but runs rather rough at an idle, and dies a LOT at the upper end of 1st gear, and occasionally dies in 3rd/4th gear (NEVER dies in 2nd).

timing belt was replaced 40K miles ago, new OEM plug wires, new battery,

when it dies, the only way it will restart is by removing the key, re-inserting the key into the ignition, and cranking back over.

doesn't run very well going uphill. my firsts thoughts are throttle body injectors going bad, bad FITV/IAC, ICU/ICM, bad plugs, or a bad relay.
ive already checked the plugs, they look like they've been replaced in the last 10K miles, ive checked the ignition/lock cylinder, all connections are snug and wiggling the key does NOT kill the engine. are there any other causes i should look for? i havent checked the primary and secondary injectors yet, nor do i have the means to test the main relay or ICU at home. i just want to see if there are any other common causes for such issues before taking them to NAPA to be tested.

any help at all is great, so if you have any experience with such issues, please, by all means, dont be afraid to share.

any help on the topic is good.

 

Have you tried new plugs, cable, & distributor? I had the same issue where the engine randomly dies and lags from 2k RPM and goes fine again. I replaced all three and it went away. I am sure one of those three fixes the issue.