QuestionNeed some help with my 1990 Celica ST. Yes I realize it's an old car, but as most of you have probably enjoyed it's been very reliable. About 2 months ago it started to have some acceleration trouble on the first start of the day. Then it became every start of the day. I would describe it as choking for air, with slight bucking.
Specifically, in second and third gear, as I get to about 2800 RPM, the car stops accelerating. I can put the pedal to the floor with no change in RPM, but I can maintain the speed where it happens. It has also happened in first gear, and rarely in fourth. Of course by the time i'm in fifth gear I'm usually pretty high on the RPM and haven't noticed it there.
The car is a 1990 Celica ST 4 cylinder 1.6 liter manual transmission. I've owned it since 1992 and have taken great care of it since. Miles are 147,000, so still young by Toyota standards. I should mention the car was in storage for 3 years while I was in Japan in the military, but I've had it out for 5 years now and this is a recent problem.
What the dealership did over the month that they had it:
First they cleaned the throttle body - they said there is a known issue like this. No fix.
Changed the throttle position sensor No fix.
Then they thought contaminated fuel (so did I) and cleaned the fuel system forward of the filter, and emptied the gas tank. The in-line filter was still good, but they replaced the main filter. I didnt know there were 2 but I'm not mechanically inclined. No fix there either.
Then they thought fuel pressure or volume. Volume is within spec and pressure is slightly high but also in spec they said. They checked pressure with the car driving and in idle.
Then they said the 99% fix was replace the fuel injectors, and looking at the old ones, I agreed it was a good idea. After changing all 4, the problem remains, although I certainly have more power available, the failure to accelerate is still common and fairly predictable.
Can I accelerate out of it? Not by stepping on the gas. What happens is the RPM stays, and may rise slowly before BAM - instant RPM and the car leaps into acceleration. What I typically do when it happens is upshift, and slowly accelerate until I hit about the same RPM where it happens again. Then I upshit again. It's a slow process where I'm never in the meat of the gear for good acceleration, and can be dangerous in certain traffic.
1500 dollars and one month in the shop and I have the same problem. The dealership is here in Montgomery AL and they are stumped. The rest of the car is fantastic, with a new paint job, new brakes, battery, ball joints, and religious oil changes. I hate to give up this car for this one small thing. The last suggestion the dealership had was the computer. By the year of 1990, you can guess it's an older computer, but they had no faults with it. Of course the older computer doesn't provide all the fancy data the new ones do so it was hard for them to be confident. Really really looking for some ideas here - I love this little car, and just to TRY a new computer could cost 4 digits since they aren't just lying around. The big stumper is that it doesn't always happen, but when it does, it's always around that RPM.
From other posts I've seen I'm thinking maybe oxygen sensor, vacuum lines or along those lines. Dealership seemed fixated on fuel system.
Thanks in advance!
AnswerO2 sensors won't affect driveability that drastically and incorrectly installed emission control hoses won't either.
Normally I would say to check the air intake system for any leaks from the airflow meter to the throttle body but in this case the dealer should have caught any leaks when the worked on the throttle body.
The computer is always the last suspect so I don't think that's the problem either.
Did any check engine lights come on in the past?
The only thing I can think of at this time that may also be the cause of the power loss is that the catalityc converter is disintegrating and clogging up the exhaust system, this failure won't turn on the check engine light on the early OBDI diagnostic system but you may or may not get an O2 sensor failure code.
The cat can be removed and checked, if it is the problem a bunch of the material from the inside will fall out and the screens on the end will be burned out, if that's the case replace the cat and the muffler.
