It idles a little high, then drops down and almost dies, then jumps back up to idling high again, then drops back down to almost dying again. what's the problem??
2006-08-19 16:39:51 · 13 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ Chevrolet
My '89 is fuel injected.
If yours is,too, clean the idle air control valve.
If it's carbureted, re-build the carb.
2006-08-19 16:47:10 · answer #1 · answered by mnm75932 3 · 1⤊ 0⤋
Well 89 are all injected...305 or 350 they are tbi or (Throttle body injection
0...It sounds like a vacuum leak. If you start the truck then look at your hoses..squeeze the hoses that go to the injestion unit...if you hear a difference of idle...up or down you have found the problem..no need to spray stuff..on the hoses but you can or use a dye that is used under a black light...good luck
2006-08-19 16:57:25 · answer #2 · answered by njctd03 2 · 0⤊ 0⤋
I have a 91 gmc that did the same thing. I took it by the car lot that I bought it from.They unpluged the little hose that went to the EGR valve and it started running smooth again. If your standing at the passengers fender looking at the tbi its a little (1/8") plastic tube thats going from the passengers side ,center to the rear. You can pull it out with your fingers , if it doesnt help stick it back.This was 2 yrs ago and it still runs great.
2006-08-20 03:06:17 · answer #3 · answered by Thomas H 4 · 0⤊ 0⤋
dont sound like many of these answers helped you much first of all you should start at yhe vacume lines it is possable but unlikely check the oxygen sensor carbon build up will cause this the throttle positioning sensor (tps ) some say this wont cause this yes it will cause this problem and you want to check the manifold air pressure sensor (map sensor) check the distributor cap make sure there are no cracks in it check to make sure all plug wires are in good shape
2006-08-19 19:00:57 · answer #4 · answered by firefightingexpert 5 · 0⤊ 0⤋
its a vacuum leak ,this vehicle has a throttle body not a carburetor ,more than likely the gasket under the throttle body is bad,or the idle air control,the tps has nothing to do with this drivability problem
2006-08-19 17:01:53 · answer #5 · answered by Anonymous · 1⤊ 0⤋
first ,you will need to know if fuel pressure is running 12 to 14 lbs.if ok ck to see if throttle plates are allowing fuel to puddle up in t -body .something over looked when diagnoising condition called hunting. shaft wears enought to cause plates to close off. fuel and air are restriced. i assume timing is correct. IAC valve must be working if idle is up and down.
2006-08-20 04:54:00 · answer #6 · answered by deltech 4 · 0⤊ 0⤋
Could be a vacum leak ...take a can of starting fluid and spray it on the vacum hoses....if the engine races then you have found the leak.
2006-08-19 16:48:11 · answer #7 · answered by ? 6 · 1⤊ 0⤋
Sometimes a vacuum leak can cause this. Check your vacuum lines, intake gasket, and carburetor gasket.
2006-08-19 16:48:01 · answer #8 · answered by cybrog 4 · 2⤊ 0⤋
check for vacumn lines disconnected,blocked tank breather.Take cap off to check that.
theres a couple things to check,good luck
2006-08-19 16:48:05 · answer #9 · answered by frank m 5 · 0⤊ 0⤋
Crap in the jets in the carb. Run some gumout or some other brand of carb cleaner through it.
2006-08-19 16:45:23 · answer #10 · answered by Stuart 7 · 0⤊ 1⤋