Hi im new on this so dont go hard on me lol
i got a grand cherokee 2006 with the engine 4.7 and i changed the sparks plugs i changed the egr valve also checked the catalyst converter with a thermal thermometer and one was bad and i replaced too also cleaned the tb now i dont know what to changed and the car symptoms are when its on parking and i press the gas to see the rpm and they normally go up without problem but as soonest i put it on drive and try to move the car moves but just feel sluggish and hard to move it takes some seconds to start getting the rpms up and if i turn the ac its almost impossible to move fast never gets up of 20 mph also when i press all the gas down to see if it works better it felt like doesn’t wanna change gear unless i let go the gas and press it again forgot to say the check engine light it doesnt have a code its just blinking and turna off and again starts blinking
kinda lost here and really need the car to go work thanks for your time

 

You are having trouble with your RPM's not rising how they should, and getting your Jeep to accelerate properly when it is in 'D'? This is only happening it sounds like when the engine has a load on it huh..

The RPM's rise normally for you when you press the accelorator while you are in 'P'?

Have you tried manually shifting? Taking off from a stop with the gear selector put in '1'.. and then moving the gear selector to '2', to see if it accelerates normally doing it that way?

 

Yes i did its still the same just buy a vacuum tester and its saids on the gauge late in timing putting some smoke tomorrow and see if i can see the leak just scare that saids something about timing its that normal?

 

So, this is at idle, the vacuum reading is much lower than normal? What do you suspect right now to be causing it?

 

I just did the timing chain replaced and still does the same hard to speed,sluggish,losses of power any clue were to look now?

 

Have you looked at your air filter? The description you just gave sounds like it could be due to a restriction of air.. Is it possible you may just have a dirty clogged up engine intake air filter?

 

I did it looks white not oily or nothing

 

That would of been nice and simple. I wonder if there is another way to have developed an air intake restriction of sorts?

I will think some.. Is there anything you are leaving out having not yet said, or any more information? I am driving on the highway right now.. will be for the next few hours

 

I did a compression test and everything was on 130 thats good took every coil out and injector as well and they all good

 

There are a lot of different things that are able to cause a loss of power and sluggish acceleration.

A restriction at the air intake or exhaust? A dysfunctional air intake management system related to sensor faults? A fault in the fuel delivery system?

I am thinking maybe it is a fuel delivery issue? Do you have access to an OBDII scanner, to use the live data feed function? I would look at short and long-term fuel trims while hooked up in the live data feed. You may ultimately see the PCM attempting to compensate for what appears to be an overly lean, or even rich condition?

A fuel pressure gauge may read a normal psi when you are testing in park without having the engine under a real load.. You can hook up a fuel pressure tester gauge in a certain way; leaving it connected, and looking at the readings on the gauge while driving to see what psi you are getting at the fuel rail while driving with a load on your Jeep.

Do you know how to use your vacuum gauge, to look into wether you possibly have an exhaust restriction?

If you have an OBDII live data scanner hooked up, you can drive around and monitor the sensors.. such as the TPS sensor. The CPS (Crank Position Sensor) could also be the reason? The CPS informs the PCM to instruct some of the other sensors and different modules how to performe, and can cause many issues outside of just having 'no spark'.

The battery terminals, battery cables, and all of the grounds are also suspects. If any of these are improper, they can cause many different types of poor running conditions to occur.

Mostly, I think something could be wrong with the fueling, or the air intake and exhaust.

 

I did a fuel test and it was good i have the obdll but Havent tried to see the live data on it and indid the vacuum gauge and all it saids it was 15 hvac i just went under the car and saw that my crankshaft sensor was full of oil and the cable too took it out to test it and i dont get any resistance voltage dont know if this sensor it’s supposed to send me a code on the check engine light but so far no resistance on it i maybe wrong when i test it but couldn’t make it to send me any voltage and i have another crankshaft sensor from another car and that one send me 4.9 or something like that gonna try to change it and see what happens i let everybody know thanks

 

Forgot to say when i took the crankshaft sensor out it was full of oil and the magnet was barely sticking to any metalnot like the other one that i have that was stronger magnet i dont know if this its something or not to pay any attention to it

 

Since you already have the sensor and are planning to change out the old CPS, I think that is a good idea. This sensor certainly is able to cause the exact symptoms you are experiencing.

When you swap out the CPS, I would recommend going to the pigtail harness in the engine bay, where the CPS leads up into connecting to the main wiring harness. I think it would be a good thing to pull the connector apart here and clean up the connection some where it connects at the main harness. Make sure the connection located at the CPS sensor itself is also cleaned up real well too, especially since oil is all over located at and near this sensor right now... A faulty malfunctioning CPS is not ussually known to throw a diagnostic trouble code, or CEL either.

You said your CEL, the check engine light has periodically flashed on and off right? There might be a diagnostic trouble code attempting to be displayed? If so, you should be able to find out what it is with your scanner. Be aware though, any code that gets displayed may be unrelated to the actual source of the problem. It may simply be thrown by the PCM after being picked up somewhere else, being affected by the real problem...

 

Updating .- i change the sensor and it work fine now it makes the car change gears like normal but still no power on the car feels so heavy,
try the live data and checked the stft that are supposed to tell you the % of the gas and its said -38% on bank 1 but normal on bank 2
also got the code p0172 since the change of the crankshaft sensor
some clue cuz im really out of options

 

-38%? How did you get this?

What is the other number? You also want to know the total trim number from the two. LTFT needs 20+ seconds idle, loaded, loaded more..

When looking at fuel trim on a scan tool, it should be checked for at least 30 seconds at three different engine speeds: idle, 1,500 rpm and 2,500 rpm. If you make a scan tool recording while driving the vehicle, you can see how fuel trims change under changing loads.