I have been having problems with my 96 buick for over a year, even the dealer gave up on it. the car starts up at 1500 and creeps up to 3500 sometimes. Makes it very dangerous to drive. I have changed
The dealer changed the folloing parts:
PCM-reman
Sensor th
sensor as
value kit connector pipe
module el

replaced lower intake gasket, upper intake end gaskets replaced fuel rail and performed all tests suggested by TAC
changed the computer twice and updated the computer as well

they had no more suggestions

sometimes when driving the revs increase to 3500 4000 and increases the speed and this creates a lot of dangerous problems

still no luck

would appreciate any help

Just suggestions:

My first guess would be bad throttle body / Mass Air flow sensors (MAF). The throttle arm could even be sticking. The second guess would be an air leak someplace judging by the parts the dealer replaced. If that were the case, the engine would be running rough. If you wish to test for a suspected air leak, one sprays starting fluid on the outside gaskets and listens for a change in engine rps.

If the problem is intermittant (you have been driving it for a year) and it's not running rough, then it's more likely it is a misbehaving sensor on the throttle body. My guess would be the MAF sensor which measures air flow going into the engine and tells the PCM how much gas to inject. I believe the MAF sensor is a flatish sensor on the top of the throttle body on your model car. In earlier models, this sensor was located between the air filter and the rubber air intake hose. Try tapping on this sensor while the engine is running and listen for a change in engine rpm. Also check that the throttle plate isn't sticking.

My last suggestion is radical. Replace the entire throttle body unit probably with one from a junk yard. That changes out all the key sensors and the possibility of an air leak in that area. You've already spent enough coin already and this would be a cheap hit or miss fix-it attempt.

Don't rule out the throttle posistion sensor. I can make my car idle at 5000 rpm just by moving the TPS arm. The dealer (if already replaced it) may have incorrectly adjusted it, which accounts for the 1500 rmp start. Normal is ~1100, then slowly descending to ~700. That, along with an air leak, could cause what is happening.

Also, the Idle Air Control valve may be bad. The longer it's on, the more air it lets in.

If you simply unplug the connector for these sensors, to computer should run off defaulted variables for that sensor. If you unplug one, and the problem goes away, you might need to replace the sensor.

Thank you for your suggestions -idling revs still to high.Sometimes I can get the idiling speed falls below 1200revs.Iget to do this by turning the ignition on let it run for 4 to 5min,rev is still flutuating between 1800 to3500revs. I switch off the engine. wait for a while and turn the engin on again the revs drops to 1500 to 2000rpm.Let it run for a min or so. I switch off the engine wait for a min or so and start the engine again , the revs drops to around 1500 to 1000rpm and flutuates.When steady at 1000rpm I put it into Drive and go.The engin is not running rough when I get to drive the car. As to your suggestion,I replaced the entire throttle body unit from junk yard, with all three sensors that came with the throttle unit. The three sensors in questions are :- idle air control,throttle positions sensor and mass air flow sensor. I regreat to say I still have the same problem.-idling too high at start up. I observed that when I unplug the elecrtical connector from the throttle position sensor the rpm drops dramatically. I still have to try your other suggestion for air leak by spraying stating fluid. Do you think it could be in the vacuum pipes or connections somewhere. I bought "Haynes repair manual" for buick, oldsomobile & pontiac 85 to 02.This does not show detail run of all vacuum pipes that are connected. Ialso noticed that when cooling fan comes on the rpm goes higher. Do you think there could be something wrong with oxygen sensor.If I unplug the oxygen sensor and start the car would it cause dammage to the catalytic converter. As you know I am not a mechanic it is only a suggestion. Another suggestion is PARK/NUTRAL switch.Haynes repair manual talks about idle air control (IAC) valve operation chapter 6-12. Quote :-Park/nutral P/N Switch indicates to the ECM when the transaxel is in park or neutral. This information is used for transaxle converter clutch (tcc) exhaust gas recirculation (EGR)AND IDLE AIR CONTROL (IAC) valve operation, end of quote. How do you adjust throttle position sensor on 96 buick. Anxiously awaiting your further suggestions,Thanking you once more Pravin.

To YOGI 123 Thank you for your suggestions -idling revs still to high.Sometimes I can get the idiling speed falls below 1200revs.Iget to do this by turning the ignition on let it run for 4 to 5min,rev is still flutuating between 1800 to3500revs. I switch off the engine. wait for a while and turn the engin on again the revs drops to 1500 to 2000rpm.Let it run for a min or so. I switch off the engine wait for a min or so and start the engine again , the revs drops to around 1500 to 1000rpm and flutuates.When steady at 1000rpm I put it into Drive and go.The engin is not running rough when I get to drive the car. As to your suggestion,I replaced the entire throttle body unit from junk yard, with all three sensors that came with the throttle unit. The three sensors in questions are :- idle air control,throttle positions sensor and mass air flow sensor. I regreat to say I still have the same problem.-idling too high at start up. I observed that when I unplug the elecrtical connector from the throttle position sensor the rpm drops dramatically. I still have to try your other suggestion for air leak by spraying stating fluid. Do you think it could be in the vacuum pipes or connections somewhere. I bought "Haynes repair manual" for buick, oldsomobile & pontiac 85 to 02.This does not show detail run of all vacuum pipes that are connected. Ialso noticed that when cooling fan comes on the rpm goes higher. Do you think there could be something wrong with oxygen sensor.If I unplug the oxygen sensor and start the car would it cause dammage to the catalytic converter. As you know I am not a mechanic it is only a suggestion. Another suggestion is PARK/NUTRAL switch.Haynes repair manual talks about idle air control (IAC) valve operation chapter 6-12. Quote :-Park/nutral P/N Switch indicates to the ECM when the transaxel is in park or neutral. This information is used for transaxle converter clutch (tcc) exhaust gas recirculation (EGR)AND IDLE AIR CONTROL (IAC) valve operation, end of quote. How do you adjust throttle position sensor on 96 buick. Anxiously awaiting your further suggestions,Thanking you once more Pravin.

There should be a yellow, black, white sticker on the top of the radiator that will detail where the vacumn goes.
If unplugging the TPS causes it to actually work better, then it may be that it is at least part of the problem. Like I said before (I tried this on my dads '02 yukon out of curiosity as well), simply moving the arm on that sensor can make both vehicles rev up to 5000+ rpm at zero throttle.
Simply unplugging the O2 sensor will NOT cause Cat. Conv. damage. It will make the SES light come on, but other than that nothing. The O2 is going to control more the fuel mixture, not RPM, so I think it is unlikely to be the problem.
P/N switch is also not supposed to have a major effect on RPM. In P/N, RPM should be slightly lower than in drive. In drive, it tells the computer that it should engage EGR, and also to open the IAC valve further to keep the car from dying in gear. Also, it tells the computer that it is safe to engage TCC. Overall, this will have an effect on gas mileage, not major rpm fluctuations.
It is normal for rpm to increase when the fan(s) engage.

What does it idle at when the TPS is disconnected?
Does it matter if the IAC is connected?
What does it do if the MAS is disconnected?

When TPS is disconnected it idels at around 1000rpm.I also sprayed WD40 to look for air leak, there was no noticable difference in change in revs/min.When MAS was disconnected it did not do anything, it hoovered around 1500 1600rpm.Also disconnecting IAC it made no change in rpms.
thank you Pravin.

Okay. The most likely problem is that the TPS is either broken or mis-aligned (if it an adjustable one). Autozone should have the sensor for around $25, and they might even put it on for you.

OK I bought new throttle position sensor from NAPA
I think it is non adjustable type. I carefully removed
the old one noting its position and put the new TPS
exactly as the old one. Started the car rev went to
1500rpm then creeped up to 2000rpm, stayed there
for a min. then went to 2500rpm. unplugged connector to TPS RPM DROPPED to 1000rpm.
thank you PRAVIN.

If it isn't an adjustable sensor, then maybe the pin is bent on the throttle body. Unless it is a wiring issue, which it may very well be based on what happened. The fact that the idle significantly drops when it gets disconnected tells me it has something to do with the sensor or possibly the wiring. You can test the resistance of the sensor, see if you can adjust it to a different setting, or test the wiring. Make sure if all else fails that when the connector is on the contacts are making contact.
You could probably take the new sensor back if you want, seeing as how it didn't eleminate the problem.

Ideling high----The throttle position sensor connector has three wires,the center wire was replaced by BUICK dealer I can see the new wire routed on the outside to the computer box and the old wire is tucked back and taped.I also replaced the whole throttle body and checked the pin and lubricated the butterfly.Tapping on MAF sensor did not help.Also changed this sensor no effect.
Thank you ,Pravin.

Now that I find odd. GM dealer replaces the center wire only. If that wire was questionable, it may be that the others have the same problem. I would definately find out why that wire was replaced, and it might be a good idea to replace the connector. Also, if they said that the wire was broken, it might be a good idea to replace the other two as well.
I'd also be suspicious of any other sensor in the same circuit as the TPS. Dealer might know which sensors, if any, that might be.

I have a 1997 Lesabre and I'm having the same problem with High idling at start up. I have not replaced anything on the car as of yet, as I have 169,000 miles and contemplating getting another. What I have noticed is that if I turn off the ignition and manually depress the throttle cable a few times under the hood and restart the car it will idle normally. I am noticing that car runs a little rough during normal idle. I'm not sure If I want to invest the time and money of replacing all the sensors, maf, iac, etc. I also tried removing the oil filler cap to see any changes in vacum.
ndgo88

Hellow ndgo88. I did what you suggested manually depressing the accelerator cable under the hood few times then starting the car.RPM is still too high 1500 to 2200rpm.My car only 62000mls.
Buickmaster, I asked buick delear about the center wire they said it was just tryel and error to see if it works.I changed TPS connector no lock. I disconcted one coolant temp sensor another I could`ent find they are on same run as TPS sensor
wire. Still no change in rpm. Pravin

See if you can get somebody to re-wire the sensor, as well as replace the connector. That would be my best advice at this point.

I have a 95 LeSabre doing the same thing. Have not even started to try and fix it yet, any updates?

I had the same problem with my 92 lesabre.the idle was going from 1500 to 2500. bY tapping the tps connector i had various egine reactions. replaced the connector with used one, now i driving car with second trainy w/o 4th gear and very low throttle under 1000rpm. where can i buy a tps connetor.

It is a very high chance it is the Throttle Position Sensor. Did it get wet? Washing the engine? I had this problem happen yesterday. I unplugged it and ran the car for about 10mins, I also tapped it a few times. Then it dried up. It works great now. It will make the ECM thing you are steping on the gas peddle. It will do this at IDLE, if u have a bad sensor.