Something else to check is your O2 sensor. I had similar symptoms on my 91, and the diag light indicated it was running lean. I replaced the plugs, wires, fuel filter, cleaned the injectors, etc. The problem was finally resolved by doing the O2 sensor.
Took 10 mins to do. Just disconnect the front engine mounts, use a bar to lever the engine forward, and hold it there with a block of wood behind the alternator or with straps. The O2 is on the exhaust manifold just before the merge. Disconnect the plug, unscrew it (normal thread), replace with new O2, and reverse steps.