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FIXITMAN
FIXITMAN, Master Technician
Category: Cadillac
Satisfied Customers: 17238
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH.
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I have a 2000 Cadillac Escalade that was purchased new and

Customer Question

I have a 2000 Cadillac Escalade that was purchased new and it has been a fantastic vehicle until about 2 years ago when it would want to speed up all by itself when placing it in gear. It would shift and go up to about 30 mph. Once driving faster to 50+, it would stay at 50 by itself. I replaced the IAC and it was good for about a year when the same thing started once more. I replaced the IAC once more and it was good for about 6 months when it started acting the same once more and this time I replaced the IAC with two different new GM parts and it now does no good. Now, I have had two ASE mechanics work on it and have replaced the TPS and throttle gasket, EGR, the ECM with latest updates and it still does it every day. I noticed that for some strange reason it runs perfect when it is raining out so I flushed the radiator and added a new thermostat with no results. We sprayed everywhere looking for a vacuum leak. There is nothing wrong with the throttle pedal or linkage.
Submitted: 1 year ago.
Category: Cadillac
Customer: replied 1 year ago.
Just wanted to mention that once in awhile it will drive correctly but when I stop for a few minutes and restart it will go back to wanting to drive by itself.
Customer: replied 1 year ago.
Also should mention that it runs perfect during a hard rain and the temperature in the 70's.
Expert:  FIXITMAN replied 1 year ago.

Hello, my name is Bobby. Thank you for the question. Can you tell me if the check engine light is coming on?

Customer: replied 1 year ago.
never a check engine light
Customer: replied 1 year ago.
Are you still here?
Customer: replied 1 year ago.
HELLO...........???
Customer: replied 1 year ago.

What is going on????? I gave you my credit card information yesterday for my 2000 Cadillac Escalade and you ran it thru for $5 on the 6th and $28 on the 7th which caused my credit card company, CHASE, TO NOT PAY IT BECAUSE OF THE TWO TRANSACTIONS and I received a phone call from CHASE this morning asking if it was FRAUD. I have been asked to give you the credit card info AGAIN which I did. Gary XXX XXX XXX XX

Expert:  FIXITMAN replied 1 year ago.

I am sorry Gary. I was not online earlier today. I do not control the charging of your card, I am just here to help with the question. If you would like to continue I would be more than happy to help. Please let me know and we can continue.

Customer: replied 1 year ago.
Expert:  FIXITMAN replied 1 year ago.

Thank you for getting back with me. Most of the time this issue is caused by either a failing throttle body or an issue with the mass air flow sensor. The throttle plate may be sticking at times and is causing this, or the sensor is reading incorrectly making the computer think that more air is coming into the engine then what really is. These are where I would start. I have also seen a failing fuel pressure regulator or intake gasket cause this also.

Customer: replied 1 year ago.
My ASE mechanic has checked everything you mentioned today and a
new MAF sensor was installed with no change with my problem. There is nothing wrong with my Throttle Body
and I had mentioned that in my original question.
Is there somebody else that may be able to help me with an answer??
Expert:  FIXITMAN replied 1 year ago.

I would like to continue to help you with this. If you want me to opt out I will and it will open the question up to other experts.

Customer: replied 1 year ago.
I am open for anybody to help with my problem so if you have another suggestion I would appreciate it.
Thank you, Gary
Expert:  FIXITMAN replied 1 year ago.

I would love to continue with you. Can you tell me if it occurs every single time you drive it? The reason I ask is because I have seen a lot of intake gasket issues that can be hard to find without a smoke test because most of the time the leak is on the bottom side of the intake. Also, the coolant temperature sensor may be not reading the right temperature. Has this been verified with a scan tool? If not see if it is reading colder than it should. if it is then the computer will add too much fuel.

Customer: replied 1 year ago.
Once in awhile for short distances like from my house to our factory about 1 mile away and this includes getting up to 56 mph, it will run fine but when I shut it off and restart 10 minutes later, it will take off by itself. I had posted this earlier above:Just wanted to mention that once in awhile it will drive correctly but when I stop for a few minutes and restart it will go back to wanting to drive by itself.I have a new MAF sensor in right now and after installing it yesterday it drove great around our residential neighborhood for about 5-6 minutes with the idle dropping down to 500-600 rpm when I let up on the gas but when I went up to 55 mph, it wanted to stay at 50 mph and would not drive right after that and the idle wanted to stay at 1500 rpm. I will be taking off the new MAF sensor Monday and install my old one. My mechanic has had the scan tool connected numerous times including yesterday and can not find anything wrong. The MAF was reading around 8 to 8.5 at idle on the 5.7 engine.
Expert:  FIXITMAN replied 1 year ago.

Did he monitor the coolant temperature while running it? Most of the time this is overlooked by mechanics.

Customer: replied 1 year ago.
I will ask him Monday but I am quite sure he did. I also mentioned earlier that I flushed the radiator inside and out and installed a new thermostat and coolant because I had noticed that the problem seems to possibly be temperature related.
He checked the temperature with his scanner at that time and said it was good. Why in the world does it run perfect when it is being driven in the rain???
Expert:  FIXITMAN replied 1 year ago.

If it is driving perfect in the rain then that typically means that it runs better in denser air due to a sensor not reading correctly or something it getting moisture in it. Most of the time it is simply because the computer calculated the mixture different. The readings typically most affected are the MAF, MAP, and O2 sensors. A poor reading coolant temperature sensor will amplify this issue.

Customer: replied 1 year ago.
I will get with my mechanic Monday and have him read your answers to see if something can be tested or rechecked.
Thank you, Gary
Expert:  FIXITMAN replied 1 year ago.

Thanks Gary. If I come up with anything else prior to that I will let you know. Otherwise have a great weekend.

Customer: replied 1 year ago.
Just spent some time with my mechanic and he said that he has checked and rechecked everything that you have mentioned with the scanner, even while driving the Escalade.
When I get up to 50-55 mph, the rpm is about 1500. When I want to slow down, the rpm stays at 1500 even if I put it in neutral and will not slow down to 600 until after I come to a complete stop.
The mechanic wants me to ask if you have heard of a coast clutch in the tranny?
Thanks, Gary
Expert:  FIXITMAN replied 1 year ago.

It is possible that the transmission is not releasing through the converter when coasting. You would know if you put it in neutral when coasting and it changes.

Customer: replied 1 year ago.
I do not understand you last comment. I would know what when putting it in neutral and what changes??
I guess you have no other ideas of what the problem may be?Gary
Expert:  FIXITMAN replied 1 year ago.

When decelerating or when coming to a stop, if you put the vehicle in neutral will the rpm's drop or remain too high?

Customer: replied 1 year ago.
I said this above earlier today??????When I get up to 50-55 mph, the rpm is about 1500. When I want to slow down, the rpm stays at 1500 even if I put it in neutral and will not slow down to 600 until after I come to a complete stop.
Expert:  FIXITMAN replied 1 year ago.

Thanks. I think that your mechanic is missing something, whether it be a sensor signal or a timing issue from a worn timing chain. I am going to go ahead and opt out of the question and allow other experts to see what they think. Hopefully you will get further help from there. Please do not respond or rate as it will then lock the question to me.

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