1995 buick lesabre every once in a while my engine will race

A few possibilities:

1. Defective throttle position sensor (TPS);
2. Bad idle bypass circuit or idle circuit solenoid;
3. Cracked intake manifold, throttle body assembly, or bad throttle body gasket (most likely);
4. Serious vacuum leak somewhere.

The most common cause of a non-starting car is the battery. It is either weak, (low voltage) dead, (zero voltage) or has bad connections. (corroded or loose) I will assume you have a fully charged battery with good connections. (both to battery and starter relay)
If you remove the starter switch lead (small wire) from the starter relay and apply +12v from the battery to its respective prong or lead on the relay, and your starter cranks, your starter switch is faulty. (not to be confused with your key switch). If you jump the two large wires together on the relay and it cranks, then the relay is faulty. If you jump the two large wires together and nothing happens, then starter is faulty, or wires to starter are loose or broken. Picture of starter switch prong on the relay is pictured. NOTE: sparks are to be expected, so don't be too scared. Pictured is a starter relay that is seperate of the starter, on models with starter and relay mounted together, its very similar.


If you car has an immoboliser system, it may be faulty.

Replace the air filter its clogged.

I saw exact same problem for few days. Now I see check engine light all the time and engine speed is normal.
The cruise control stopped working. Cruise control sign so nOT light up when I turn it ON. Nor does it works.
But car seems to work fine.

Could be the choke getting stuck.
Check your distributor cap for any cracks, and they can be very small. I would replace it anyways. It is very typical that they give you trouble in the cold, and work when hot, when they are cracked a little.

If it knocks at 50 it will knock sitting still if you race it up. Is the oil pressure good? These motors hardly ever have a bearing problem. The only knock problem was the harmonic balacer that comes apart and knocks. The rubber falls apart and it will make a knock sound all the time, more with the ac on. If you have a knock at 50 or highway speed only you may need a outer tie rod end only. Get the front end checked as they will make a knocking sound on the highway. reply

if you are racing the engine up to 4000 rpm in park, you may be hitting the rev limiter - if while driving you have be seeing the start of an ignition problem

Check your coils. Make sure that they are working properly.

I would Look For A Vacuum Leak, Given the Fact that ALL that Work was Done in a SHORT Amount of Time, And The Brakes ARE VACUUM ASSISTED, that when Brakes are applied the ENG. Light Comes on, Seems to Me It all May be related. It does not take Much to Pop A Vacuum line OFF Accidentally

If you have replaced the Throttle postion sensor (TPS) or have replaced the battery, sometimes the car will need an engine set up.
I had the same problem with my xj6 and I did an engine set-up and it has been fine for the last 2 years. Also with the idle doing what it did it had a very harsh shift when driving and changing gears.
The BAD news is the dealer has to perform the engine set-up using the WDS (worldwide diagnostic system) The set-up will set the kick down switch, it will calibrate and set the TPS and also perform an oxygen sensor orientation test.
With the set-up it will allow the TPS sensor to be adjusted to the correct factory specs.
Sorry you can't do this your self.
This is obviously if there is no vac leaks and the throttle butterfly is set to 2 thousands of an inch. (gap on the side when closed throttle) check with a feeler guage.
JPTCAT