wsaxon10

Truck takes longer than it should to crank and idles high for about a minute. The coolant does not overheat but it runs a tad warm. I checked the codes KOEO and KOER and did not find any insight to a trouble condition. Truck is a 5spd m5pd, 2.73 gears. I have checked the TPS with a voltmeter only to find it was in spec. MAP is getting both the 12v and 5v PCM. I can not check the Hz of it as of yet. However unplugging that module I would assume causes the pcm to use a default value. It starts and idles like a champ with the MAP unplugged. Steady 20lbs vacuum on manifold. No manifold or vacuum leaks. There is the coolant sensor, IAT, and EGR sensors I have yet to diagnose, except that the vacuum for the EGR (green line) responds accordingly to how open the throttle is. I drive this truck 160miles a day round trip 4 days a week to work and back and gas is taking a bite out of student loan and living costs. I budget down to the dollar to make life easy for myself and my wife I just married. 17.5mpg might be acceptable for some but this same truck used to get 25+ under the same driving conditions on same route. I am not afraid to put on my thinking cap and break out some tools to isolate this gremlin, but at this pointt some assistance would be greatly appreciated.

raski

Try cycling the key on/off several time to run the fuel pump, then start and see if that changes its behavior.

wsaxon10

I did this after letting the truck sit over the weekend while I was away before making my trip. It did not make any difference. I bled fuel pressure from the Schroeder valve. I did tap on and use a touch of canister air on the map sensor nipple, and while the truck fired right up and idled high it did not idle as high as it was. I had disconnected the MAP and TPS previously, so of course when I ran the KOEO test I got codes for the TPS, MAP and IAT. That is what I know of, I might not have read the two digit codes correctly. I might have gotten an 11 but I was in a hurry. I cleared the memory and drove the 80 miles to work, and I will do the test when I get the engine warmed up again tomorrow to report some more codes. The truck did start much better than it would have when I stopped for a soda, but since I ran it harder than I normally do I can not speak for fuel economy yet.

I am beginning to think that there is not really a senor issue but more or less a wiring harness issue. I have only located the non-EFI harness schematics on google. Again I will be re-running both KOEO and KOER tests tomorrow after my shift.