So I replaced the crankshaft position sensor. What a job! So it can be done from the top with a 1/2 inch deepwell socket on a 1/4" drive socket. It isnt easy. I ended up removing the grommet, installing the sensor, then trying to replace the grommet, then removing the sensor, putting the grommet back in first, lubing up the vaseline, then installing the sensor. It took me hours. I am a mechanical engineer, but that didnt stop me from cursing the entire engineering community!!
I came real close to removing the transmission dipstick, but I didnt.

Anyway, that issue is solved. Timing issue seems gone in my test drive. Now I need to tackle the 2000+ rpm idle.

 

I put the old IAC valve back in and it got me down to around 1000 rpm. I can live with this. It’s curious to me why the old part works better.

i plan to pull and clean the throttle body.

It bothers me that I can’t get rid of the p0505 code too.

 

Do you notice any rpm change at all when you first start the motor? Here is a more in depth explanation of the code.

 

I guess I was too quick to declare victory. After driving for 15 minutes today on the interstate, the problem has returned. It is there immediately after cranking again now. I am coming around to the idea of getting a new ECM. What is the best place to get one?

 

There isn't one. It's really a crapshoot if your 'new' ecm is any better than your original.... I would be more inclined to talk to your local parts stores, see what their pricing is like. That way, if you have problems, you can talk face to face with a real human being.

 

I replaced the ECM. It seems to have fixed the idle control issues. I now have no codes. My engine is still running like crap. Doesn’t want to load up, bogs down and backfires when I floor it.

 

Scan for pending codes.

 

There are no pending codes.

I idle fine, but if iI hit the throttle I get Complete loss of power and backfiring. I have to accelerate slowly to use the vehicle.

I have 3 comments:

• Doesnt this condition usually mean lean conditions?
• My fuel gauge doesn't work. I read in the service manual that misfire detection and other codes are suppressed if you are low on fuel. Can i jump something to make the truck know it has fuel to get passed that?
• I notices that my intake air temp sensor was reading 160 degrees when i monitored it through OBD. Could it be that simple?

I'm going to get a temp sensor and a throttle body gasket today, but it will likely be a couple days before i can do the throttle body cleanup job.

 

Clogged cat?

 

I don't think so, seems like plenty of exhaust flow. Plus after various levels of testing it has worked fine intermittently until it warms up. I dont think a clogged cat would ever work. How would i test that? Remove the entering o2 sensor to give a flow path?
In the driveway in park it thrives at any rpm. You wouldn't know I have an issue until you add load to the engine.