Ok so I've had a check engine light basically since I got the truck back together and it was because I had the IMRCs taken out but they were left in the tune. I decided to check them last night and there were some different ones this time. They were p0171 and p0174, lean bank 1 and 2, p0704 clutch pedal position switch malfunction and p1121 tps inconsistent w/ maf. Now the clutch pedal I assume is because of having to change the clutch master cylinder and I didn't get the connection back on all the way or something like that. It still works and allows me to start the truck and everything so I don't think it's too big of a deal. The others I'm not quite sure about. I think it might be becaise the truck still doesn't have its final tune but wanted your guys' input. Could it not being tuned exactly right cause those codes? What about the TPS inconsistent with the MAF? Does that seem more like the TPS or the MAF are going out? I'm going to clean the MAF cause I haven't cleaned it yet and see what that does but any other ideas as to the other codes? Any input I'd really appreciate.

 

The 171/174 is most likley un metered air, - A intake leak or vacuum leak, - It might have something to do with your other DTC's , most likley it does.

As far as trans, the PCM program uses input like this, MAF TPS Trans SFT. So it all sounds related.

 

Ok thanks, I'll do another check for vacuum leaks. What do you mean by trans? The clutch position switch?

 

Your PCM samples readings from the MAF, then throttle position, then trans (gear in your case) for AF's.

 

Oh ok, I just didn't realize that the PCM took so much information from the manual transmission. Thanks for the help.

 

Respectfully, if you are intenionally leaving out parts for whatever reason, the PCM can detect the end results.
The IMRC absence is hurting low end torque.
If there are unsealed holes left for air to enter, it will result in lean codes.
You cannot just make changes to these systems on an adhock basis thinking it will accomplish some better end result.
It just gets you deeper into issues.
Good luck.

 

No offense taken. I removed the IMRCs when I rebuilt the engine knowing that it would result in a loss of low end torque. I did however have the holes for the IMRCs welded over and smoothed them out when i ported/polished my intake manifolds, heads and everything else. I am just wondering if the added air flow from removing the IMRCs now allows could be what is causing the lean codes. All of the air is theoretically coming in through the intake and is being metered by the MAF but I wasn't sure.

 

Found a leak where the gasket around the IAC on the intake was missing a piece last night. Fixed that and it seems like that was the problem. Thanks for your help guys. I'll let you know if that fixes it for good or if it comes back.