1988 Chevy Celebrity Engine putting/stalling at idle

On my 1988 Chevy Celebrity, 4 cyl, 2.5L, I only have 147,000 miles. I went to work one day, it was fine. When it was time to leave, I started my engine, and it stalled and putted. WHen I put my foot on the gas, it was fine. I proceeded home, and at every light, when I pressed the brake, it would act as if it was going to cut off. Once I got home, it wouldn't start. The "Service Engine Soon" light never came on, but abruptly went off. As soon as I put my foot on the accelerator, it ran fine. I had the coil pack module changed, tested the coil packs and they were fine, and installed new spark plugs and wires. Now, it's running, but still stalling or putting in idle. Checked the fuel pressure and it's running at 13 psi, which is normal. Replaced fuel injector, EGR valve, and crankshaft sensor a few months ago. Where should I go from here?