First of all, I am very new to this forum and if this issue has been addressed somewhere else...please let me know! Secondly, I am a seasoned mechanic in both air and ground vehicles, although, I have been known to become frustrated with an issue and miss the K.I.S.S. items. The problem: My daughters 88 XJ, 4.0 had been running with a wavering idle, slow shift response, and a sluggish take off with an very audible backfire. I diagnosed a faulty CPS, TPS, and IAC. All of them were replaced and the TPS was set correctly using an ohm meter. It ran great for a day, then the problem came back ten fold. Sans a fuel pressure tester, I replaced the fuel pump thinking a lack of pressure may be causing some of the issues. When I turned the key to start nothing happened at all. I have power to all engine sensors, lighting, and interior electrical items. All relays in the engine compartment have been checked, the start relay is functioning properly, the battery is less than 24 hours old with a good charge, all grounds have been checked and refreshed, the starter checks out with an external jumper switch, and I disassembled, cleaned, and reassembled the Neutral Safety Switch which ohm'd out good in all gears. I even had a spare ECU that I plugged in to see if that was the issue. Of course I also had a spare Ignition Switch that I threw in to no avail. I still have no power to the start relay! Today, I decided to buy a new ignition switch and after connecting it and turning the key, it cranked for less than a second.....then nothing...No power in the start position! Could a bad fuel pump cause all of this? If so, could that faulty pump fry an ECU? At this point, I'm ready to gut it and drop in a 350! Any help, idea, or kick start would be great at this point! Thanks in advance!