Stalling problems

DJ!

MEMBER
1999 JEEP GRAND CHEROKEE
4.7L
V8
4WD
AUTOMATIC
177,000 MILES

I did not have any problems until one day when I shut it off it did not want to start back up. It seemed like it was not getting gas at first unless you hold the pedal to the floor then as soon as you let up it shuts off. The first code that popped up was speed sensor. I replaced that and both o2 sensors and nothing. I changed the cam sensor and the crankshaft sensor still nothing. I pulled the ECU, PCM and steering column out of another Jeep that was running just fine and still nothing. Before I changed that it said something about fuel injector eight and after I changed the computer the first code said fuel injector four and now it does not say anything about injectors, but keeps popping up both o2 sensors and speed sensor when they where replaced first. I am lost and need help.

7 Replies

HMAC300

MECHANIC
48,601 POSTS

First thing you need to do is put the original PCM in unless you do not have it. then have a mechanic program the security feature in as it should have been done if you keep the replacement pcm then scan for codes and check fuel pressure with a gauge auto parts rent it. that may be one of the problems is the pump. then clean the throttle plate on both sides and IAC hole with choke cleaner. finally check your fuses under hood as some O2 sensors have a fuse, see link.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

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Monday, April 10th, 2017 AT 9:36 AM

DJ!

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4 POSTS

Thank you I have another question though, I looked in the fuse box and there is no fuse in either spot where it says the o2 sensor fuses are but that would mean it has not had any sense? I got the Jeep and it was running fine until then. I think it might be the fuel pump also I just need to test it and see first. But would it be the pump if it still runs when you give it gas? It just does not like to idle. If you let it idle or let off the gas to fast or put it in gear and try and go it just bogs out and shuts off.

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Monday, April 10th, 2017 AT 9:57 AM

HMAC300

MECHANIC
48,601 POSTS

The pump may not be giving enough pressure and volume, it can run but giving it gas may not be enough. You should put them in it is for the O2 heater relay so it means your heaters are not working in the O2 sensor. That may be a problem as well cause they cannot read fast enough.

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Monday, April 10th, 2017 AT 12:00 PM

DJ!

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4 POSTS

I plan on getting those anyway, but I do not see that being my main problem sense it worked fine for as long as it did, but I am still getting them. Is there any chance the throttle body sensor could cause any of these problems? I know before it all the sudden started running like this where I cannot even make it more then a few feet out of my driveway. The only issues I had with the way it ran at all before was the idle bouncing around a little.

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Monday, April 10th, 2017 AT 12:32 PM

HMAC300

MECHANIC
48,601 POSTS

It could be but if you scanned for codes and it was bad it would show up my guess you just started replacing parts without scanning which auto parts does for free.