Tahoe 2003 mysterious stalls

[bowtie2]

Hello,
My 2003 Tahoe, 5.3L stalls everytime after 30 mn drive from a cold engine, living me on side of the road suddenly, I then need to wait 30 other minutes to let it cool down, and it starts back straight for a couple more minutes. Anoying and dangerous. When the engine runs, it spurrs like a dream, no vibrations or defect codes. Display shows sometimes "reduced engine power or batterie charge" message for a second before stalling, but not everytime...
What I already did: Put a new Delphi sending unit and filter, cleaned throttle body, Map and Mas sensors cleanings, new battery, cleaned all ground cable bolts on the engine block and even add a new one.
So I 'd love to read the solution of this very common problem...
Next try: a new crankshaft position sensor and new TPS sensor.
Any idea (there is another thread in the Performance section, with a number of people facing exactly the same problem, without appropriate solution, maybe in this better chosen section some readers will help)

 

[livingez_123]

Have you checked your fuel pressure?

 

[OR VietVet]

Googled and found this:

This 2003 Chevrolet Tahoe with a 5.3 liter engine came in with the customer complaint of the reduced power display was on and the vehicle could not be driven more than about 30 mph. Checking codes found a code p1516 stored for Predicted VS. Actual Throttle Position Correlation Error. That is fancy computer talk for the computer expects the TPS to be in one position and it sees the TPS in another position. There are several things that can cause this condition but by far the most common is a faulty throttle body assembly. I have noticed a disturbing trend in these vehicles in that the last few that I have had to change I also found very weak batteries and the weaker the battery is during cranking the more pronounced the symptom. If the key was left on in these vehicles for more than about five to ten minutes (the time it takes to hook up a scanner and check computer codes and relative data), the starter would turn the engine over very slowly (indicating a weak battery) and sometimes the battery would have to be jumped to start the engine. I may be wrong but it is my belief that a weak battery condition during cranking may be leading to premature failure of the throttle body assembly. My personal philosophy on late model highly computerized vehicles is to replace the battery every three to five years regardless and of course use a good battery and not the cheapest you can find.
Anyways on to changing the throttle body assembly. First remove the upper engine trim cover by first removing the screw and lift off.


Found this also:


Joe I'm not real sure about your problem, but there is a module box mounted on your firewall. It is right in front of the driver side. This box has two plug-ins on the bottom of the box. Facing the truck,the plug on the left will give you both of those messages if it has been unplugged.Check to see if it is plugged in good. Hope it is as simple as this.If this is the problem it might take the check engine light a couple of times cranking it up and shutting it off before it goes away. The REP. message should go away as soon as it is plugged back in. Hope this helps.



Found this:

I have an 03 Chevy Tahoe, 5.3L V8. I am getting the error P1516 Reduced Engine Power. I have taken it to several shops. Most recently they replaced a modulator that is located in front of the driver, bolted up against the frame closest to the driver. I never suspected this part, but he wanted to try it. I advised them to check the G103 Ground Wire as stated in the TSB for this issue. They said they bypassed that ground by grounding somewhere else, and that wasn't the issue. On diagnostic check he said the TPS and TAC were showing no discrepancies when he was able to duplicate the Reduced Engine Power. Now he wants to replace both sensors and the throttle body. I think this is a waste of time, but I don't have another solution. The problem only presents in the morning. After stopping and restarting 5 or 6 times it will let you drive it the rest of the day. I believe this is because the computer is set to test the data sets when the car goes from 40 degrees F to some magic number. I really am not mechanically skilled at all, but I know a little. Any advice is appreciated.


Found this also:

A) Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing. The wiring for this and the throttle body quite often causes problems.

B) Verify that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.

C) When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing an individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture
Info.



It appears that a lot of this overlaps and may well be a source for you to track down the problem. Especially the first one.

---------- Post added at 03:34 PM ---------- Previous post was at 03:26 PM ----------

More that points to the TAC or throttle body:


this can be caused by a misfire or a fault in the TAC system(throttle actuator control) I would start with getting the truck scanned for trouble codes and a good throttle cleaning would help. This throttle body can get carbon build up and it throws off the base throttle setting. I use the GM cleaner(15$ at dealer) and a soft pipe brush. The dealers do a full service for 150$ that includes the injectors, air induction and throttle body cleaning. This is important maintenance for these trucks.

these are also known for intake manifold vacuum leaks and if the fuel pressure is low it will cause running issues and not set the check engine light.

 

[Marv02]

It could be the computer getting hot then shut it self-down.

I had an KTM Dirt bike after riding it for a while the CDI ignition would get hot and stop working and after it cooled down you could restart the bike until it heated up again then the engine would quit again.

This took me a while to figure out what it was after I installed an new used CDI never had stalling issues again.

 

[bowtie2]

Thanks for your infos.
As I am writting this answer, the vehicule is cooling down in a street nearby! I tried today a TPS module change with the Dorman replacement device. Easy change, but I didn't want to use their new plug with all white wires. The truck did start very well and idles perfect like with the original module, so I went for my test drive...this time, 5 minutes later I was facing engine cuts, then a complete stall along side the road. I waited 30 minutes, but the vehicule was acting permanently with cuts. I will go and drive it home when completly cooled down, because it doesn't even start up again...
For info, the battery is all new from last week. I don't have the way to test fuel pressure, but sending unit and filter are all new too, it could be the pressure regulator, I will try to press the valve on the engine fuel line to see if I see good pressure.
This time the check engine light is on, so I will look for the code it shows, and no warning messages on the dash when it was about to stall.

 

[bowtie2]

Ok, the default code shows P0336, Crankshaft position sensor, which is very logical. I will change it as soon as I get it through my mailbox (I live in France).
I checked that these sensor have to be re initialised, so let's hope it won't be necessary. I also know that the starter removal is very difficult on my Tahoe, but no choice, I have to change it.
If it's not that, I will have the car towed to the garage and cross my fingers they fix it and don't kill my wallet!
Anyway, I will write down the end of that issue on this thread.

 

[andrewg29]

Hello,
My 2003 Tahoe, 5.3L stalls everytime after 30 mn drive from a cold engine, living me on side of the road suddenly, I then need to wait 30 other minutes to let it cool down, and it starts back straight for a couple more minutes. Anoying and dangerous. When the engine runs, it spurrs like a dream, no vibrations or defect codes. Display shows sometimes "reduced engine power or batterie charge" message for a second before stalling, but not everytime...
What I already did: Put a new Delphi sending unit and filter, cleaned throttle body, Map and Mas sensors cleanings, new battery, cleaned all ground cable bolts on the engine block and even add a new one.
So I 'd love to read the solution of this very common problem...
Next try: a new crankshaft position sensor and new TPS sensor.
Any idea (there is another thread in the Performance section, with a number of people facing exactly the same problem, without appropriate solution, maybe in this better chosen section some readers will help)

Had this exact same problem with my tahoe.. I replaced the fuel pump and have not had the issue since.

 

[bowtie2]

Hello Andrewg29, my pump is new, you were lucky fixing it this way!

 

[bowtie2]

Today I worked on the Tahoe and decided first to put new spark plug wires, they were original and 115000 miles old. I put good new AC Delco quality ones. Doing that on the right cylinder bank, I remarked a little water coolant coming out one of the 2 heater hoses. The clamp was loose, for how long? no way to know that. I secured it properly, and followed the water leak traces, which were going down to the starter... and for sure (because) I can't see it running on the crankshaft position sensor plug for the moment but it's sure on it's way. It can really be a cause of this sensor failure in my opinion, coolant may have cause rust or simply shorts inside the plug connector. I willl do a road test to see if when dried the CPS doesn't make the engine to stall. Anyway I have to change that asap.

 

[bowtie2]

OK, no luck, I was pretty sure these 2 last parts change didn't help. Vehicule stalled again after a 10 mn drive...