90 Celica 54SE Engine Problem

[geoii98]

I have a automatic transmission in this car. It has high mileage but runs pretty good. However, occasionally the car starts to idle up and down and when I let off the gas while driving sometimes gets real jerky and then smooths out by itself or when I give it gas. When I come to a stop sometimes it idles up and down and then cuts off. I have found that if I unplug the battery for a few minutes the problem goes away for the biggest majority of the day but eventually starts happening again. I have changed the plugs, wires, and distributor cap. I even tried a new idle/air control valve and throttle position sensor and got nothing different. I have also put a new fuel filter on it with no results. I am thinking possible vacuum problem. It also has a real rich exhaust smell while running. I have gotten the codes of 25 and 26 which is too rich and too lean. I replaced the oxygen sensors as well with no results. The car runs great so long as my foot is on the gas. ANY IDEAS?

[NotoriousScrat]

I know this one is simple bu have you checked your intake hose? Mine cracked once and my problems were somewhat similar (though not completely)---although that doesn't really explain the battery thing. Still, it's something to look at.

[geoii98]

Originally Posted by NotoriousScrat

I know this one is simple bu have you checked your intake hose? Mine cracked once and my problems were somewhat similar (though not completely)---although that doesn't really explain the battery thing. Still, it's something to look at.

I bought a new intake hose and put it on. That is actually when the problem began.

[geoii98]

Originally Posted by chester08

Chester08: Maybe it didn't work because of the quality of intake hose you bought. Try to find a better one. They're a lot out there for sure.

Thanks for the info...but I put the actual Toyota part on it. I have never put any aftermarket on this car. That's probably why it is still getting 33 miles to a gallon and has 225,576 miles on it. I am thinking the problem is vacuum related just can't find the problem area.

[RIP]

Have zero Celica experience so can only speak to basics. Oscillating idle is an indication of a vacuum problem. You are on the right track. The tinniest crack can create major problems. When you changed the air duct I would imagine you disturbed EGR vacuum lines. Take a very close look at those and the vacuum line going to the brake booster. If those are good spray brake cleaning fluid around the intake manifold gasket. If the idle changes in a particular spot that may be your problem.