..."pumping" the accelerator pedal added fuel to the engine on fuel injected vehicles. The Enrichment System on your vehicle is not working while in the "START" mode. This is the equivalent to the choke and/or accelerator pump on a carbureted engine. And frankly, I don't know the whole process of fuel enrichment, either for starting or accelerating, on a fuel injected engine. If it were my car, I'd take it to the dealer as they have all the test gear for the proper operation of fuel injection.
My Wifes 1999 Cherokee Sport Has been reluctant to start only when cold. In Order to get it started we need to pump the gas and then it will start with a big blast of Black smoke out the tail pipe. If i do the old Two foot drive method and drive it for a few hundred feet it stays started and seems to run fine. I've replaced the Fuel pump mudule, Plugs and wires. I evan found a broken Vacuum line. After all that it's still acting the same. It seems Once it's in Drive it comes alive! Any Ideas? TPS?