Corolla Runs rough when cold

Go to the Toyota dealer and ask for an AAP diaphragm. (Auxilary accelerator pump) It is located on the outside of the carburetor with three screws. It is a little tricky but not that hard. be sure not to lose the spring under the diaphragm. You will probably need a very stubby little philllips screwdriver. you do NOT need an entire carb rebuild so don't let anybody tell you you do. The diaphragm is leakin raw fuel into #1 cyl and to a lesser degree #2. This system is shotdown by a thermal vacuum switch after warmup hence the problem goes away.

Don in Austin

Thanks a million for the advice.....I never would have thought of this. Makes perfect sense as the #1 cylinder and #2 cylinders do not fire when cold. I have limted backyard mechanics skills so it sounds like this is something I can attempt myself. Thanks again....(NAPA wanted $450 for a rebuilt carb).

Doug and Patty

Yes, you had it right...the car is a 1989 Corolla....sorry about the typo. I picked up the diaphragm tonite at the local Toyota dealer...a $42 piece of plastic.. Is the AAP located on the drivers or passenger side of the carb? Thanks again.

Doug and Patty

Hey Don in Austin....thanks for the post...I was pulling spark plug wires ( with car running) trying to isolate the open loop miss firing and determine d the miss was at cylinder #1 when engine was cold. I was going to replace the plug, but then ran across your post. You are a life saver. BTW, I bo ught the '89 Corolla a year ago with 42000 original miles from an 85 year o ld man, you wouldn't believe the condition....like new! I've have 5 people come up and offer to buy the car...its hard to believe people even notice this 89 "bare bone" toyota.

Thanks again buddy, Brent