What does the scanner think reference voltage is?? Should be 5 volts. Vary too much from that, and things start to get strange, as it throws off ALL the sensors. Reference voltage being off would go a long way to explaining why idle gets crappy once the engine goes into closed loop....

How is your gas mileage doing? Better/worse than before??

 

Much worse, went from 8.5-9mpg to 5.5mpg. My scan tool isn't powerful enough to see the reference voltage. My friend has one, gonna see if I can get him to bring it over.

 

VOM would do the trick. I suspect your reference voltage is wrong.... which will throw off everything......

 

Well my friend brought his much more powerful scan tool over. I mentioned the timing fluctuating at idle. So we took a hard look at all the outputs. The interesting one was the crank counts. They were all over at idle. The graph was terrible, especially compared to the nice smooth graph the cam senor was putting out. However the interesting thing was when the rpm was brought above 1500 it smoothed out the graph and the timing advance went from fluctuating 12 degrees to only 3 degrees. Interesting the issues I have driving only have occurred below 1500rpm. Starting to think I have a failing crank sensor. Would explain why in that one video the mis-fire was so consistent, cyclical even.

 

That would make a great deal of sense. Can you FIND crank sensors for your truck yet?

 

They are out there. Rockauto has them back in stock for reasonable money. Several other sites have those and cam sensors listed too.

 

I did order one from rock auto, should be here Monday.

 

Crank sensor helped but again hasn't fixed it. Had something interesting happen though. I was checking voltage at the coils. The front coil pack was getting 6v and the rear 0v when the ASD was off. So I put the multimeter on it and had 10.8 v while cranking on both. Now they both have 0v when they are supposed too after testing. I checked the 5v signal at the Map sensor. It was 5.15v. I will have to check the TPS signal when I get some time because I am only reading 3.7v (70%) at WOT on the scan tool.

 

Yeah, you aren't gonna get the full five volts on the return signal from the TPS. All it is, is a variable resistor.....

 

According to the FSM I should be getting 4.8v at WOT. Something is up there but I don't think that is causing the issues at low throttle, might explain why it seems low on power at higher throttle positions.