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Have a 1988 comanche with a 97 4.0 Starts and idles fine after 5 minutes of driving it starts to bogg down and a small backfire sound from intake I'm assuming. Only code I have is 42. open or shorted condition detected in the auto shutdown relay circuit. An open condition detected in the ASD relay output circuit. An open or shorted condition detected in the fuel pump relay control circuit. An open circuit between PCM and fuel gauge sending unit. Circuit shorted to voltage between PCM and fuel gauge sending unit. No movement of fuel level sender detected. but I'm not sure if this is relevant due to the mismatch between the newer motor and the stock mj fuel pump. Gauge reads backwards. new plugs, wires, IAC, upstream 02. been at a loss for a couple weeks now. No other codes except battery temperature due to I don't have one. please help

I have done my research before asking you guys on this but I can't seem to put my finger on what the issue is. Latly only at idle after coming to a stop, the rpm's would go really low and want to stale then jump back up a little. Today the same thing happened but worse and there was a little hesitation on take off. But after gaining speed I am totally fine. Shifts fine and cruises fine at all speeds. SO I was thinking either a vaccum leak ( I have checked the hoses but who knows) or a O2 sensor going bad or the MAT sensor is going bad (engine temperature sensor that determines air-fuel ratio I do have a small intake/exhaust manifold gasket leak but I don't see how that would create such a hesitation. I had the gasket go about two years ago and was running fine. I have upgraded all my grounds, I have a mopar CPS and drilled out the top mounting hole, cleaned all connectors and relays, plugs and distributor are fine, air filter is fine. I would appreciate the input.