. Once it reaches normal operating temperature it runs fine. It idles fine when cold, but when I put it in gear it starts bogging down and backfires sometimes. Cleaned and tested the air mass flow sensor, no change.
Here are the common cause of surges, stalls at stops, slow idle speed, erratic idle, 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
I used almost the whole can (albeit by accident) but so far it seems to be helping, but there was a few hiccups still left today while driving it for the first time after the procedure.
×
SOURCE: buick lesabre nightmare 2
SOURCE: bogging and hesitation on acceleration iddle is fine
You definitely covered most of the bases. Considering all you've done so far, I would check into the fuel system next. First, how old is the fuel filter? Has it been changed? Yes, a bad filter can cause the problems your having. Next would be the fuel pressure regulator. You need a fuel pressure gauge to check it, which you should be able to rent from a good auto parts store. That will also tell you how good your fuel pump is, i.e. if the pump can deliver the necessary fuel pressure off idle. After that, I would check the injectors themselves for wear or blockage. A bottle of fuel injector cleaner in the gas tank would be a good idea, cheap, quick, and it wont make anything worse. If all that checks out, check your catalytic converter, a clogged or bad cat will also do what your describing. Good luck.
SOURCE: 1998 Pontiac Bonneville SE 3.8L Backfires/ Sputters
sounds like the ignition module is going bad.
SOURCE: I have a 1991 Buick Park Avenue. Runs rough in
Here are the common cause of surges, cold stalls, 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.
To correct this problem I want you to get a can of intake cleaner (ABOUT $5.00) from any local auto parts store like NAPA or Carquest, do not use carburetor spray, intake cleaner only or u will damage the Teflon coating inside the throttle valve and air bypass valve, 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.
Testimonial: "Thank you, I'm sure if your advice it was I'm looking for. But at least if this works, it will save me a lot money from having to replace expensive sensors."
402 views
Usually answered in minutes!
I used almost the whole can (albeit by accident) but so far it seems to be helping, but there was a few hiccups still left today while driving it for the first time after the procedure.
Have you had the fuel pressure checked, maybe the pump is failing.
It seems like good ideas are given for your problem. However, backfire and rough idle occurs when sticky valve stems slow the valve closing. When that happens and combustion occurs - combustion slips past the still closing valve and ignites the next load of fuel and burns.
2 things then happen. 1- it causes a cough sound. 2- the motor then falters for lack of fuel - which the slow closing valve let combustion consume. The easy remedy is explained on this educational site. Hope this helps.http://www.auto-tune-up-and-repair-optio...
×