3.4L Sensor Locations- Comment Page 2

Question: We have a 2002 Oldsmobile Alero. Recently changed the intake gaskets lower and upper. But, when put back together it idles high. What did i do or didn't do? Ran fine before hand.? Idles fast when air breather on, but when taken off idles slow. I was told to put all together and start up, and should reset the computer..any ideas?
 Answer: You might have a vacuum leak. First, try disconnecting the battery for a few minutes to see if that helped.


I just bought a 2000 Chevy Impala. It used to be a police car. Sometimes when I get in the car and start it for the first time the temp gauge is already at almost half way. Then sometimes it just has a mind of it's own. Sometimes it reads hot and then goes to cool if I turn the car off and start it back up right away. I have taken it to a shop. They said the instrument cluster is broken. Also all the fluids are fine and I see no smoke or water. I hear no bubbling or nothing of the sort. I do smell a little coolant when I get out of the car but no bad. Have any of you ever had this problem? And if you have do you have any advice? Thank You.
 If the gauge is at half way on the first start, then yes, either the instrument cluster is bad or the temperature sensor. Smelling ANY coolant is bad. Get that checked.

My 95 3.4L Monte Carlo with the cold engine/high rev - stall problem has a consistent QDM1 fault, and is showing 0 VDC input from the throttle position sensor. I checked the wiring, TPS is getting 5 VDC as it should from the PCM, and the wiring reads good for continuity and no short to ground from the TPS connector to the PCM (the sensor ground is good too.) The TPS itself was replaced recently with no change to the discrepancy. Would this be a sure-fire sign that my PCM is broke or could there be another issue at play?
 If the sensor is new and you are sure the wiring checks good between it and the PCM, then yes the computer is faulty. Although, the 3.4L DOHC motor has a common problem for high cold idle- the lower intake manifold gaskets leak vacuum. This would not give you a Quad driver fault though.

I have a 2001 Chevrolet Impala my temp gage goes to the half way mark then goes a little over then back down also my idle goes high i have to turn the car off and on about 4 times for it to go away if I'm driving and the idle goes high i change gears from drive it goes down a little but if its on park it goes really high also when i come to a stop and then drive my car boggles it only does it on first gear it feels like when you are driving a stick shift car and u let go of the clutch to soon and it boggles thats how my car drives i really need some info on whats going on with my car.
 Check coolant level. May be low caused buy a leaking intake manifold gaskets. Check ignition coils and spark plugs causing your engine hesitation.

2003 Pontiac Grand Am 3.4 GT, sometime the car will start and when it does it runs great and if I shut it off it will start again. It seems if i let sit all night it wont start, go out few hours later it will start. I replaced the PCM,BCM (used from same car). The crank sensor, ignition switch, key switch. Checked the TPS (good). Bypassed the Passlock wit a resistor (no light on) I would consider my self a good mechanic but this one has me stumped. When it doesn't start it is firing and will run on starting fluid. I can hear the fuel pump kick in and pressure is good. What do you think this erratic problem could be?
 If it runs on starter fluid, then you have a fuel pressure problem. You say the pressure is good- is that when it is not starting? What is the pressure?

2001 Oldsmobile Alero and sometimes after the car has been driven I shut off the car and when I restart it the temperature gauge won't go up even though i know the engine isn't cold and the cars RPM will go high on idle and if I try to drive it that way the car will stall or idle rough on stops. But once the temperature gauge goes to normal it will run fine. I think it's the engine coolant sensor but I'm not sure. What do you think?
 It could be a coolant temperature sensor problem, but I think a check for any trouble codes would be a good place to start. After that, you will have a better idea of where a problem area might be.

I am currently putting together a 2000 Chevy impala 3.4 and i have the whole thing finished except for one last clip. My problem is that i cannot find the receiving end. It seems like it goes somewhere around the rear set of spark plugs other that I cant provide any useful info. If u have questions ill answer on the website
 If you could provide a picture of the clip your are referring to we can help you out. Send an e-mail with attached picture to feedback @ greatautohelp .com

2001 Grand Am v6. Sometimes starts rough and even dies, once I get it running without chugging (usually hold gas half way down then clears up) the car will run like brand new. Changed map sensor. When key car on fuel pressure sometimes only hits 15, then key again jumps to 30. While running its around 40. Whats normal pressure when key on and when started?
 That's a tell tale sign of a bad fuel pump. You should have about 45psi with the key on or engine running. 15 is way too low to start the car which is why is chugs and stalls. Replace the fuel pump and filter and you'll be good to go.

2000 Chevy Malibu and after i have driven it approx. 45 minutes it dies out on me. Sometimes when i let it sit 15 to 20 minutes it starts again but not always. In addition, when the gas goes below half it dies out especially if i am going up a steep hill.
 Have your fuel level sensor checked to make sure it is accurate. Then have the fuel pressure checked, best to check after is stalls to confirm if the fuel pump is bad.

Really appreciate this website, great Job... I have a 2000 Pontiac Grand Am, 3.4 litre. While driving at a constant speed under 80kms the engine surges, rpm's wiggle a couple hundred and will continue while accelerating until speed is over 80kms. Also does it while going up hill....any thoughts ?? Thanks.
 Sounds like maybe an engine misfire- a bad plug wire? Could also be a transmission problem. The TCC or overdrive could be going off and on.

Chevy Malibu with a 3.1 Litre (2100) Engine. The car runs great and starts fine, unless it is below 50 degrees outside. The engine turns over fine, it just won't start. If the temperature is above 50 degrees, it starts fine every time. This is frustrating.
 Colder weather can affect lots of things, but mainly fuel pressure. I'd recommend a fuel pressure check when cold or when it's acting up. If you have a fuel pump that is going out, it will definitely act up more when the weather is colder. The spec for fuel pressure is about 50psi with the key on. It should hold and not drop off. You may also want to check the fuel pressure regulator for leaking internally as well.

2001 pontiac grand prix runs perfectly but the has sensor has stayed on full for the past 2 days I've had the car and I know I've used enough fuel for it to move a little bit. Any tips? When the car is off and the radio is going the fuel pin on the dash bobs back and forth..
 You need a fuel level sensor in the gas tank.

2000 Oldsmobile Alero cranks but wont start. Has spark and fuel to the fuel rail. i sprayed carb cleaner in the intake and it tries to fire. Any suggestions would be great.
 Fuel to the fuel rail really doesn't mean you're getting enough fuel or enough fuel pressure. You need to do a pressure check to make sure it's within specifications. If it tries to fire with carb spray, you are either not getting fuel, or you could possibly have a security problem with the car that is killing the fuel signal. I would bet you have a fuel pump that has gone bad, but be sure to check first.

Buick Regal it wont turn on. I replaced the power packs because the car didn't spark and now it does. We also got the starter checked its good but the car won't start. When we turn the car over it doesn't stay on even if I press the gas. I don't know what to do. We are going to check the fuel pump and fuel line next. What do you think I should do..? Help please. I'm going crazy!!
 Yes, check fuel pressure and injector pulse signal. Make sure the security light is not on the dash also.

Chevy Malibu 2002 V6 3.1. The engine is easy to hot. The temp gauge is likely to get a half of full scale. ECT sensor is not available since buy the car. Cooling fan is only have one speed only. SES is ON. Already try resetting SES by disconnect Battery in 2 hours. Please suggest.
 Well, you really need to see what code is stored in the computer that set the SES light on. If you've got a ECT problem, that would most likely have set the trouble code. You could have a thermostat problem as well, or even a faulty computer. The best place to start is getting the trouble codes retrieved so at least a diagnostic starting point can be found.

2002 Chevy Monte Carlo 3.4 cranks but wont start. Fuel pressure is 50 psi and has spark. It's not getting injector pulse. Checked all fuses, connectors, and power to injectors, all check good. I checked for codes but none exist at this time. I am suspecting a problem with the security system because of no injector pulse. How can I reset the security system to see if it will fix my problem. My scanner will not access that system.
 You can try to do a relearn. Just search our site, there are several pages about that.

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