what diagnostic scanner are you using if I may ask.
I have a XTOOL D7, it has the crossfire model. It scans then at the very end says it can't communicate with the ECU 😡

 

Mine was doing the same thing. I pulled my coils off. Everyone was cracked on the back. Replaced them and plugs and wires. Not done it since.

 

There is a vaccum port on the front underside of the intake manifold. You cannot see it. But you can get a few fingers on it. With the car running try to gently wiggle it and see if anything changes. If not spray some carb clean on it. If the idle changes, then that rubber piece that comes through the manifold is dry rotted. If it is rotten, There are a few options. You can push a small brass tube inside of it and then reconnect your vacuum line. Mine was so bad that it fell apart when I touched it. I either had to buy another manifold or fix it. Evidently that piece is not sold seperate from the intake. I pulled my manifold and split it open, then made a new piece. That job sucks. It takes 2 people to adhere it back together properly.

 

Hi Machfivexf,
You wouldn't happen to have any pictures of the vacuum port repair you performed. Is it on the passenger or drivers side of the intake manifold?
Thanks,
-Jerry

 

I do. But cannot access those at current. Waiting on a new battery for my laptop. On the NA. It is just behind the air pump. On the bottom of the manifold pretty much in the middle. After the air pump has been removed you van follow the only vacuum line that goes there. You cannot see it and barely get a finger on it. A quick test before you remove the air pump is while it is running. If it will idle. Use the tube that comes on a can of carb clean and spray in that location. See if anything changes in the idle. It attaches to the hose that my finger os touching. I believe it controls the flappers inside of the intake.

 

I found my pics of when I split the indians.

Rotten vacuum hose at lower intake

This is inside of the intake where the hose plugs in

It was also not tite where it plugged in.

Combination of hoses and a brass tube. I was testing the fit for tightness. Adapter was installed on the short end of the bend after a test fit.

When installing. I had to insert just the hoses. And they should be very hard to get into the hole. Then I inserted the brass tube using lube. I inserted the brass tube past the hole as it made the vacuum hoses tight enough to seal. Also leaving enough inside for the control to make a tight seal.

I used mercedes sealant to seal the two pieces of the intake. And also coated the outside for extra protection and in case my fix was not tight enough. I let the sealant set up for 24 hours before reinstalling the complete intake. It is still holding just fine. This was in 2021.

Another thing is the factory piece was also rotten and cracked on the inside of the intake. It had a vacuum leak inside of the intake at the same time.

This is probably not your problem. However it caused most of the symptoms that you have been describing.

 

Also found these emission tubes almost clogged completely.

 

Hi Machfivexf
Great Pic's, thanks for posting. Just another thing I have to check.
-Jerry

 

I'm hoping I found my problem. Pulled my charcoal canister one of the lines going to the canister was broken on the canister. Had to order another canister. Then I found the hose at the filter was broke to. Hope this helps.

 

That wasn't it. Still hesitating. But fixed EVAP codes.

 

@machfivecrossfire Man... wish I would have found this last week. I had this exact vacuum line and rotted piece in the same place. I am still having very rough idle and I suspect I did this repair wrong given your excellent photos. One big question... how did you get that internal piece seperated from the lower intake? I tried to figure that out and did not want to break anything so I did my best but I think it was not good enough. Any further pictures or explanations is appreciated.

 

If you are talking about that black rubber piece that looks knobby. It comes out from the inside. Its under the flapper control. It actually plugs into the bottom of the flapper control. You have to split the intake open to get to it.

 

Hesitation getting worse. Final threw a code P0101. But I've put a mass air flow sensor on in 2021. Could my evap codes missed the sensor up? I unplugged it while the car was running engine kept idling the same but the fan speed up.

 

Negative on the EVAP codes. You have a good puzzle. I have one too I'm dealing with on my SRT6.
If your car is a N/A you should consider machfivecrossfire vacuum leak above.
If you have K&N air filters, perhaps some oil has gotten to the MAF element and is causing that code. Cleaning the MAF with a MAF cleaner would clear that up.
As it is getting worse perhaps you should consider a back pressure test on the exhaust system. It is an easy test if you can get the forward O2 sensor out you place a pressure gauge in the O2 sensor hole and start the car. At idle there should be not much over a half pound pressure ideally it should be no pressure at all: bring the RPM up slowly and the pressure gauge shouldn't go above 1 lb pressure. Anything more than that indicates a restriction in the exhaust. Usually a catalytic converter going bad. You could also smoke test the exhaust system to be sure it is completely sealed and letting no air into the cats.
Smoke testing the intake system would revel vacuum leaks that could be allowing unmetered air into the intake and fooling the PTCM. Watching live data on fuel trim might give an indication and being able to graph the O2 sensors with the scan tool makes it much easier than just seeing voltage numbers jumping back and forth.
Good Luck and please let us know if you find the source of your problem.

 

Ill check that out. I've had several people ride in my car the all said its the cats. One of my friends put a motor in because he thought he had a bad motor. Then had to replace the cats. I've gotten all my evap leaks fixed and vacuum leaks there was several.

 

When i say hesitating when it stalls its like you hit your brakes. My 02 sensors bank 1 and 2 sensor 2 are flat line until i give it gas then it starts moving. Don't know much about what they are suppose to do but bank 1 and 2 will fluctuate when idling.

 

After the cars has run for a few minutes so both the engine and cats are warm the O2 sensors aft of the catalytic converter (1/2 & 2/2) should stay about 0.45 volts. They shouldn't move much. They basically monitor the catalytic converter. If you step on the gas quickly they will fluctuate, but a slow RPM increase shouldn't move their voltage much.
The O2 sensors forward of the catalytic converter (1/1 & 2/1) will show voltages between 0.1 and 0.9 volts because they are upstream of the cats the exhaust gas rich or lean fluctuates in its oxygen content.
When monitoring the O2 sensors it is much easier to watch their response if you can see them on a graph. Just watching voltages switch around can be confusing and the scanners sampling rate plays a huge part in what you will see in the voltage switching. Looking at fuel trim is usually quite helpful.
The PTCM uses the voltages from the forward sensors to adjust the fuel injectors.
Are you getting any DTC?

 

Okay thanks. I'm removing the cats next week. If this fixes the problem I'm going to put high flow cats on.

 

Not removing cats. My transmission just went. Good thing I had one bought getting ready for the V8. Transmission is going in first was wanting to do it all together. The shop said my transmission could have been some problems I've been chasing.

 

Got my transmission back the said they put dexron 6 in it. Will that work?