As stated in the title, I drive a 1999 Jeep Grand Cherokee Laredo 4.0L V6. For the past several weeks, the odometer has displayed a P0320 code without the check engine light and I have had some problems with the engine stalling at higher speeds around 60-70 mph. After letting it sit for a bit completely turned off, it would start again and run fine. Last week I scanned it with a Bosch OBD2 and I pulled several codes including: P0320 No Crank Reference Signal at PCM, P0340 No Camshaft Reference Signal at PCM, a repeat of the P0340 with "confirmed" added, Electronic Control Unit Internal Malfunction, Under Voltage, Over Voltage, and Wheel Speed Signal Malfunction on all 4 wheels. Just yesterday I went to start it and noticed that it cranked fine, but hesitated to fire. Once it was running, it was idling roughly and surging around 500-750 rpms. At points, it would drop in rpms and almost stall completely, but would surge back up to the 500-750 rpm range and sometimes up to 2000 even. I tried driving around a bit, but it would surge and topped out at about 10 mph. I disconnected the positive battery terminal today for about a minute and then started the engine, It was rough and surging for a minute as I gave it some gas when it shot up to 2000 rpms and returned to a normal, even idle. I visually inspected the sensors and wiring and it looks fine, but these symptoms make me think it's not as simple as replacing the sensors. If anyone has any possible diagnoses/solutions, I would greatly appreciate you sharing them.