Car temporarily loses power when transmission changes gears

[her209]

Car is a 1994 Camry with 252K+ miles 4-cylinder automatic transmission. When I'm driving, and the car changes from 1st to 2nd gear and with my foot on the accelerator, the engine sputters and the car loses power and then slowly catches up. It also does this when going from 2nd to 3rd. But its not there (or at least noticeable) when going from 3rd to 4th gear. No check engine light warning either. This problem occurred all of sudden and not gradually, i.e., it was working fine the day before.

After problem occurred, drove the car home and parked it in the driveway and turned off car. When restarting the car, the engine seemed to idle rougher than usual. Moved the car to the street and the engine seemed like it was going to die. However, after letting it sit for a month, the car starts up fine but the sputtering is still there.

Changed the engine and transmission oil a few weeks prior to problem appearing. Everything looked normal during oil changes. Checked the current oil levels and are within normal operating levels. Passed smog a few weeks before as well.

My brother who is more mechanically inclined than I am thinks its a blown head gasket. When looking at the coolant in the reservoir, it looks dirty with a brown color but it could be from the brown build up on the inside of the reservoir. I poured the reservoir content into a clear 2 liter bottle and the liquid is definitely brown. Opening the radiator cap reveals neon green (i.e., normal color) coolant. How do I check for foaming or milky color if coolant and oil is mixing? Do I open the engine oil cap while the car is running?

Other things I'm thinking it could possibly be:

Clogged fuel filter - haven't changed this in 7-8 years. I'm thinking as press down on the accelerator, its pushing more fuel through the fuel filter to the fuel injectors. Just a guesstimate.

Clogged fuel injector - never changed. No fuel is being injected into one of the cylinders and its running on 3 cylinders. But this should cause the engine to run rough all the time and not just when going from gear to gear...

Spark plug/spark plug wire - Changed last circa 2005/2006. Fuel is being injected into the cylinder but the spark plug or spark plug wire is inhibiting a spark from igniting the fuel. This should also cause the engine to run rough all the time and not just when going from gear to gear.

Timing belt jumped a tooth? This should also cause the engine to run rough all the time and not just when going from gear to gear.

Transmission - FUBAR'ed? Switching between gears works normally and no audible grinding noise is heard. It only occurs right after the gear switches that the engine seems to sputter.

*shrug*

 

[jlee]

I'd start with basic tuneup items - ignition components and fuel filter should probably be replaced at this point anyway, though I doubt it's the fuel filter.

How long has it been since an oil change? If it's been a while, change it and see what it looks like. A compression test should be dead easy on a 5s, since you can reach all the plugs without being a double jointed acrobat.

 

[LTC8K6]

Ignition/timing issue?

Emissions...egr valve?

 

[PlasmaBomb]

Don't open the engine oil cap when the car is running...

It should be fine to do it when it's cold - the cross contamination you are looking for will typically looks a lot like mayonnaise (give or take some discolouration). You can't miss it.

Sounds more like a transmission issue though, as you correctly identified the other problems should be more constant...

Maybe ZV or exdeath will have better suggestions, autos aren't that common in the UK and I have never had one...

 

[her209]

I'd start with basic tuneup items - ignition components and fuel filter should probably be replaced at this point anyway, though I doubt it's the fuel filter.

How long has it been since an oil change? If it's been a while, change it and see what it looks like. A compression test should be dead easy on a 5s, since you can reach all the plugs without being a double jointed acrobat.

I changed both the engine and transmission oil just a few weeks prior. Less than a month.

 

[her209]

Don't open the engine oil cap when the car is running...

It should be fine to do it when it's cold - the cross contamination you are looking for will typically looks a lot like mayonnaise (give or take some discolouration). You can't miss it.

Sounds more like a transmission issue though, as you correctly identified the other problems should be more constant...

Maybe ZV or exdeath will have better suggestions, autos aren't that common in the UK and I have never had one...

OK, with the car running (an cap closed), I checked the dipstick and the oil is normal color. After driving the car around the block, I check the dipstick again and its the same. I turn off the car and opened the oil cap. You can't see the oil but the oil that splashed up and got caught on a small ledge is normal colored. Same with the inside of the oil cap.

 

[IcePickFreak]

When you switched out the oil you would of definitely noticed if there was coolant mixed in with it. You'll also easily see it if you just check the dipstick with the engine running or shortly after you shut it off.

I'm with jlee, a compression test would be a good idea to hunt the problem down. If I had to take a guess, I'll go with a tired/stretched timing chain/belt at this point.

 

[her209]

I checked the spark plug wires to make sure there was sparking an all 4 are sparking. What I did was pulled one out and left it raised but still in the slot. Then turned on the car and looked and saw a spark jumping to the engine block. Then turned off the car and reseated the wire and pulled the next one out. Also, with the car running on only 3 cylinders, you can tell a huge difference between it running on all 4.

I also tried unplugging both O2 sensors thinking one of them may be problematic and causing the computer to misfire. The car idled normally but didn't try driving it around. No check engine light came on either.

 

[thescreensavers]

You can also get a UOA done to see if there are any traces of coolant in your oil

 

[thomsbrain]

What do you mean sputters? Like just seems to lose power for a moment? Cause my first thought when it comes to losing power between gears in an auto is that your transmission is toast.

 

[exdeath]

I suspect transmission issue.

You notice it more in 1-2 and 2-3 because those gear ratios are much farther apart than 3-4 (it's a 4 speed A140E) and the engine RPM drops way down after the shift and falls out of the power band. And the 5S-FE already lacks power to begin with.

1: 2.810
2: 1.549
3: 1.000
4: 0.706

If I'm reading your info right: When it upshifts while accelerating wide open it bogs really bad after the gear change until you stay in it for a bit, then it recovers as RPM slowly comes back up. As if the RPM drops out of the power band and the engine can't rev freely? eg: lugging.

Then coming to a stop in "D" it's running rough and trying to die? What is the RPM dropping to when it's trying to die? When it's trying to die does putting it in neutral allow it to idle correctly and stop running rough?

By sputtering do you mean cutting out and bucking erratically like something is failing under high engine load or just growling and slow to rev like if you were in too high a gear?

My eyes are on torque converter lockup clutch and supporting systems. Not only is the engine not allowed to rev, causing the resulting bogging, but you're also trying to turn an extremely tall final drive while accelerating due to lack of torque multiplication if the engine isn't allowed to slip and rev in the converter.

I can replicate your symptoms in my 95 5 speed by shifting from 1 to 2 at 10 mph and trying to step on the gas: not much will happen until about 3 days later when the RPM finally comes up to 4500+

Simple test. While you're flooring it and it seems like its bogging bad right after a shift, while keeping your foot in it, shift to neutral while it's bogged and see if the engine suddenly revs up with ease. Then lift off the throttle, and shift back into drive, and get back on the throttle, and see if it's a smooth clean transition, or a hard sudden transition with an abrupt change in engine RPM.

 

[Patz]

@her209

Did you ever find what your problem was? I am having the exact same issue. Doesn't happen all the time, but there is usually a delay going from 1st to 2nd so much so that I avoid fast merging onto highways.

My car has 67k miles.

Thx

 

[Wrsluder]

I suspect transmission issue.

You notice it more in 1-2 and 2-3 because those gear ratios are much farther apart than 3-4 (it's a 4 speed A140E) and the engine RPM drops way down after the shift and falls out of the power band. And the 5S-FE already lacks power to begin with.

1: 2.810
2: 1.549
3: 1.000
4: 0.706

If I'm reading your info right: When it upshifts while accelerating wide open it bogs really bad after the gear change until you stay in it for a bit, then it recovers as RPM slowly comes back up. As if the RPM drops out of the power band and the engine can't rev freely? eg: lugging.

Then coming to a stop in "D" it's running rough and trying to die? What is the RPM dropping to when it's trying to die? When it's trying to die does putting it in neutral allow it to idle correctly and stop running rough?

By sputtering do you mean cutting out and bucking erratically like something is failing under high engine load or just growling and slow to rev like if you were in too high a gear?

My eyes are on torque converter lockup clutch and supporting systems. Not only is the engine not allowed to rev, causing the resulting bogging, but you're also trying to turn an extremely tall final drive while accelerating due to lack of torque multiplication if the engine isn't allowed to slip and rev in the converter.

I can replicate your symptoms in my 95 5 speed by shifting from 1 to 2 at 10 mph and trying to step on the gas: not much will happen until about 3 days later when the RPM finally comes up to 4500+

Simple test. While you're flooring it and it seems like its bogging bad right after a shift, while keeping your foot in it, shift to neutral while it's bogged and see if the engine suddenly revs up with ease. Then lift off the throttle, and shift back into drive, and get back on the throttle, and see if it's a smooth clean transition, or a hard sudden transition with an abrupt change in engine RPM.

My truck is exactly as you described in your last paragraph. It has a smooth transition when I put it back in drive. If I get back on the gas at 2000 or more then there is no lugging. Are u saying that it is most likely the TC. Also it is rare at this point and very slight but if I'm in park I notice a small shake caused by a lower idle but will not happen the next time I stop. Any help is much appreciated. Thank you.