1994 Buick lesabre. starts and runs rough in spells, when driving tries to die, when step on gas gets worse and dies, if let off gas tries to idle, when doing this sometimes the speedometer goes up and down

SOURCE: 2000 LeSabre starts but runs very rough and stalls. After

My 2002 Lesabre (app 115000 miles) started something like this. Also the loose gas cap had been coming on for quite a while. I replaced the vacuum line from the air intake to the fuel sensor. It is under the engine cover (twist off the oil filler to remove the cover). There are two hoses together that come of the air intake. The small one goes to the top of the engine. The other goes across the front and makes a 180 turn back to the sensor. Chances are the 180 piece is cracked. It all comes from the dealer as one unit. $25
Seems to have fixed my problems. So if your car is running a little rough. Shutters under load. If the gas cap loose is coming on or probably a number of symptoms this might be the answer. I would replace this item. A cheap try.

Tim Carter

• 62 Answers
• Posted on Sep 27, 2008

SOURCE: 1995 BUICK LESABRE WON'T START

bad fuel pump, or fuel fuse/relay check fuse or relay first

Marvin

• 85242 Answers
• Posted on May 20, 2009

SOURCE: car dying when letting off gas

try this it might cure the problem. works for me most of the time.

Here is the common cause of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.