P0172 on 2003 dodge Ram 1500 3.7L 6 cylinder

I have been struggling with a P0172 code on my truck since April of 2021.

It all started with my original ECM throwing a P0601 code (CRC Error), which told me the ECM is no good. I purchased one from an outfit in Florida with a lifetime warrantee. Shortly after I installed the remanufactured ECM, I received the P0172 code.

I have replaced the following parts:

All 6 spark plugs (Autozone)

All 6 coil on plugs (rockauto.com)

All 6 fuel injectors (rockauto.com)

Fuel rail (rockauto.com)

Throttle position sensor (rockauto.com)

Map Sensor (rockauto.com)

Positive Crankcase Ventilation (PCV) Valve (autozone)

Idle Air Intake valve (rockauto.com)

BOSCH O2 sensors (up stream and down stream) (Autozone)

New Air Intake Temperature sensor (MOPAR, Dodge Dealer)

Vapor Canister purge valve (Autozone)

MOPAR O2 sensors (both) (MOPAR, Dodge dealer)



I mentioned where I purchased the parts because I am not having doubts of the quality of the parts that I have been receiving from buying online.



After doing all this work myself, I took it to dodge dealer who has a computer to read the 2003 Dodge modules (all the other local dealers told me they could not work on the truck that old). They told me that the O2 sensors needed to be replaced even though there was two brand new BOSCH O2 sensors on the truck. They explained to me that after market O2 sensors did not work as well as the original parts. $1000.00 later I still have the P0172 code, but, in addition I started to get the P1195 code. I took it back to the dealer and they replaced the O2 sensors again (against their will).

After the dealer threw their hands in the air and said they would need to disassemble the engineer to continue to trouble shoot, I took the truck back. I contacted the vendor who supplied the aftermarket ECM and they agreed to send me a new (remanufactured unit) to try to help me out. I installed the 2nd after market ECM and had the same result, P0172.



I thought about trying another place for the ECM, but at $500 a shot, it is very expesive.

I use a remote (wireless) OBD2 scanner to monitor while I am driving. After the dealer replaced the O2 sensors for the 2ndtime, I do see the P1195 pop up into the pending codes and disappear and even rarer yet, it even sets as throwing the code into active state, but disappears on it’s own.

I have checked using a smoke generator and could not see any Vacuum leaks around the engine nor under the truck.

I have checked the compression and all cylinders hold around 90 PSI (if I can remember correctly). The truck has 270K miles (I try to keep the oil changed every 3K miles), I have never had any serious mechanical issues internal to the engine.

My symptoms are: slow/ sluggish acceleration and lack of power climbing hills. I often have to move to the right lane climbing hills because my speed goes from 65 mph to around 50 mph at 4500 rpms. The OBD2 reports a calculated 58% horse power being used.

I have checked the oxygen sensor for a dirty CAT, but, I am getting a steady 0.84 at 2500 rpms (for the most part, it may dip once in a while). The entire exhaust system is original.

Recent development is that I have experienced 3 or 4 backfires on acceleration.



I have been driving illegally since June when my inspection expired, but, I do not have another vehicle so I am stuck. Any help would GREATLY be appreciated.

 

I would restest compression. 90 is too low. Lack of power indicates those numbers may be accurate......

 

Thanks HeyYou!
I will double check compression tonight when I get home, after work.

 

OK, so I checked the compression again and I was way off, Unfortunately, I did not read the instructions until after I did the pressure test. I did the pressure test with the engine cold. Should I redo it with the engine warmed up?
cylinder one has 177 psi,
cylinder two has 183 psi,
cylinder three has 168 psi,
cylinder four has 182 psi,
cylinder five has 170 psi,
cylinder six has 163 psi



I forgot to mention in my original post, I was looking at my mode six diagnostics information and found that TID test number 11, 13, 52 and 53 were in a failed state.
I tried googling mode six diagnostic codes, but I did not find anything. Does anyone have mold six diagnostic codes for TID 11, 13, 51, 52, and 53?

 

I'm not an expert on the P0172 code, but will tell you what I would do in your situation.
I'd first look at the plugs to see if they show a rich condition. I say this because backfiring can indicate running rich. If rich, then problem is likely fuel monitoring (O2 circuit) or fuel delivery (high fuel pressure or improper injector cycling).
Then just for an experiment, I'd remove the O2 sensors, leaving the holes open on the cat, and drive up that same hill that I bogged down on earlier. Is the performance any better? My thought would be restricted air flow which would explain sluggishness on acceleration under load.
I think goal here is to narrow down the problem as best you can.
For the mode 6 diagnostics, those codes are not easy to find. I think I would talk to someone at an emission shop to see if they had more detail on what the particular codes mean. I assume the TID numbers you mention have dollar signs in front of them.
Did you fail emissions, or are you thinking you would fail emissions with your current codes? It might be worth it to get the truck inspected then get more info from the inspector, even if you fail.
Sorry for the lengthy response. I don't think I can give you good info until we know more.

 

I am not sure why my posts are not posting, but, I answered jrsick twice and do not see my posts. I do see my picture of my spark plugs in the gallery, but, my post don’t show up, anyways, here we go again.



Thanks jrsick for answering. I put a picture of the spark plugs on my post, but I will post this with no picture to see if I can post. The plugs look fine, they do not look like they are burning rick, if anything, they look like they are burning lean. (if this post makes it up, I will post pictures of the spark plugs separately or you can see them in the gallery),

I can take off the O2 sensors, tie them up under the truck and see what happens. As I am traveling this weekend, I may not be able to do it until next week.

BTW, the TID codes do have a $ sign in front of them (TID:$11, TID:$13, TID:$51, TID:$52, TID:$53) I did not know the significance of the $ sign.



I have not take the truck to get the emissions inspection because in New York State, if you have a CEL on for any reason, it automatically fails inspection, so I have not even tried.

 

 

 

Yeah, couple of your posts were awaiting approval, but, as you already had the info up, I nuked 'em.

Those look suspiciously like 'rare-earth' spark plugs. So far as I know, the newer engines don't like 'em much either. I know they cause all sorts of interesting problems in the 2nd gen trucks.

 

thanks HeyYOU!!! would you recommend champion or dealer plugs? what do you think of the condition? What did you think of the compression readings.