GMC Sierra 1. 50. Questions rough idle, stalling, loss of power. Hello there John. Thanks for all your replies and help here. It sounds like you know what. Microsoft System Center Data Protection Manager 2006 Chrysler. I dont know if you know about Lexus at all, but I. SC4. 00 that has been an absolute NIGHTMARE trying to. I havent brought it into Lexus yet because they charge a fortune for. I dont trust the dealers around here after getting. But I have brought it to my trusted. Broadband_oxygen_sensor-lrge.png' alt='Installing Air Fuel Ratio Sensor Symptoms' title='Installing Air Fuel Ratio Sensor Symptoms' />If you have ANY. I should try next it would be greatly appreciated. Here. are my symptoms. The check engine light is usually on, but it turns randomly and back. How%20to%20Replace%20an%20Air%20Fuel%20Ratio%20Sensor%20-%202%20check%20engine%20light%20illuminated%20on%20the%20dash.JPG' alt='Installing Air Fuel Ratio Sensor Symptoms' title='Installing Air Fuel Ratio Sensor Symptoms' />It was not on at all when I bought the car, but after I. WOULD start back up but then stall out right away again. Then it. started fine after sitting for a few hours. But I had it towed in anyway. Also in the MORNINGS only when it was cold, it would take a few. But if I turned the key to the drive position for 1. I was told that meant I had. So I figured the dying out was my fuel pump going. I have it towed to the shop as I said Please bare with me here. I need to get to. OK, it. tested fine they said under the pressure test. But I hear these tests are not always accurate I still suspect it could. I need to tell you my issues and how the car. Everytime I bring it. I need a new part, which has not fixed the. First they told me I needed a Crankshaft Positiion Sensor. Mass Air Flow Sensor Testing,P0171P0174 System Lean. Vehicle 2001 Land Rover Discover II Codes P0171, P0174, TCM Incorrect Gear Ratio Symptoms NONE, Slight pre. Resistance chart for both Coolant Temperature SensorandManifold Air Temperature. Computer code told them I needed it. Well, I am 9. 9 SURE I did NOT need that sensor. Never had any. symptoms of a bad crankshaft sensor. My car always started up. Your engine needs to put in the right amount of fuel for the amount of air coming into it, that is, the proper airfuel ratio, to deliver the best power and fuel economy. FAILED to start, which is what happens when that. So I fear the computer might be giving the wrong codes. I had an idea that MAYBE my problems are tied to a bad Computer in. Should I try to replace the main ECU for the car I recently replaced the FUEL PUMP ECU, the 2nd time I brought the. DIED again, same symptoms, stalled out and it WOULD. I kept trying to get it to. I could not. So I knew I got ripped off on that. Crankshaft Posiiton Sensor, as it never fixed the problem. Also I forgot to mention that AFTER they put that sensor in, my car. NEW problem which they denied causing, but it NEVER did. I brought it to the shop The new problem, which is really. Car is COLD, it STUTTERS AND. BUCKS EXTREMELY BADLY. Infact the RPMs are hard to get over. RPM. And it wont go faster than 2. MPH when its cold. As it. starts to warm up, it stop bucking so much unless I hit the gas harder. So, the symptoms are COLD I barely hit the gas and it. Stutters. HOT I can hit the gas LIGHTLY and it wont stutter. I can drive over 2. MPH. lol But this is soooo annoying that they. It all started after they put that CPS Sensor. Crankshaft position sensor which I have no idea if its connected to. I think they might of messed up some wires or created a. So I bring it in. I needed a FUEL PUMP ECU. So, I bought one and had a Fuel pump ECU installed, and since then. This was only 2 weeks ago the car has NOT stalled yet, but I fear. Who knows. But I am more worried about this BUCKINGSTUTTERING problem, as. Even then it. doesnt seem to run as good as I can never hit the gas hard to speed. Another thing which I find strange is that my Check Engline Light was. NEVER on before I brought the car in there, and it even had a SMOG. I bought it. I think they may have messed it up and caused. Light bulb was just burned out and they even. I believe they are honest, as the reviews. I never had a bad experience with them. I think they. just have NO clue how to fix a Lexus. I am leaning towards something to do with the MAF sensor although. I also have a REALLY BAD SMELL Not. Smells like I am running rich or. There is definitely some kind of problems going on with. I said before the Check engline light turned off for a BIT. Fuel Pump ECU Also they claimed they. And they said they. Spark Plugs and those were good. PLEASE HELP Anyone, if you know what part I should try to replace. Should I try the fuel pump itself I. Ive read online. Or should I try. MAIN CPU for the car Because I can get one on. Ebay for 3. 0 so it would be really cheap, and I could have them put it. They have run out of ideas themselves, they said they have no clue. Which I hate to hear supposed car experts say. I really need to fix this before it really damages my engine. Also I. am sure it wont pass smog like this. I just put over 5k into this car and. I have to get another smog test in a couple of months. If I cant. figure out whats wrong I will have to lose the car and all the money I. Nobody would even think about buying it in this kind of.