I called it fixed too soon.

[Whiskey]

Okay,.. I have a second problem, this is a new one,.. and thankfully it's getting worse - I'm hoping it will give out entirely soon and make it easier for me to solve

I was driving to work today, stopped at a stop light, it turned green, I hit the gas and the car barley moved.

I gave it more gas, and still it barely creeped.

Hit the gas further, it sputtered a little.

Then I floored it.

The car coughed and took off.

It stumbled once more while going up a hill - but the rest of the drive to work went fine.

Right now I'm guessing maybe Throttle Position Sensor (Do Corollas have one of these? Does anyone know how to test it?) Or maybe Fuel pump not keeping pressure up I have a gauge for that and need to test it. What numbers for fuel pressure am I looking for?

Do Corollas have a Fuel Filter? I can't find one down by the frame rails, if it does, where is it? The previous owner said that he never replaced it,.. so that's a possibility too if there is one.

Thanks for the help!
Whiskey

[jmk1977]

crummy fuel pressure could cause this.

you check plugs?

is it intermittent?

[Whiskey]

Plugs are less than a week old, wires are 30,000 miles old.

It is intermittent - most of the time it's okay,.. constant speed it seems okay,.. maybe a little jumpy, but It's mainly when the engine is under heavy load (Such as steep hills) that it acts up, or on acceleration but once again it's intermittent sometimes it accelerates fine. It idles great, there is no check engine light.

Thanks,
Whiskey

[fishexpo101]

Fuel filter is inside the gas tank - part of the fuel pump assembly. The "sock" you can get to easily, the filter itself, you'll have to partly disassemble the pump.

TPS is a possibility, though unlikely. Question, when it stalled the first time, was the ground level? Have you ever noticed it stalling in that manner if the front of the car is pointed downward. Could be a bad pump or faulty pressure regulator. Could also be a clogged injector or bad coil pack - those can be intermittent in nature, so it can be tough to pinpoint and nail down.

[Whiskey]

It has never stalled entirely - only sputtered and failed to accelerate, once I let off the gas it will idle normally. It never misses at idle, the idle is smooth.

The nose of the car is always flat, or pointed up - but I think that's simply because going downhill I don't ask as much from the engine.

This fuel system does not appear to have a return line - so the pressure regulator is electronic and part of the fuel pump assembly right?

Thanks for the ideas! Is there a good way to rule out a clogged injector or bad coil pack?
Whiskey

[jmk1977]

found a great video.

Run your car 'let it warm up and run at a stable idle'

Unplug a spark plug and note the change in 'sound\rpm' plug it back in and move on.

When you get to the cylinder that has little effect on the engine whatsoever that is the one having problems.

However if your problem is intermittent it is likely to be something else. possibly electrical or funk in your tank?


See: fishexpo101

[Whiskey]

Yeah,.. that's great for diagnosing a miss at idle,.. but that's the weird thing - it always idles perfectly fine. It's only under load, and intermittently at that when it surges, shudders and struggles.

Whiskey

[jmk1977]

out of my league.

It is to diagnose weak cylinders.

Not foolproof but gives a good idea.

I'll leave this solution to the experts, sorry for not being of much help.

[Whiskey]

I appreciate the advice! Thanks for commenting. I'm stumped too

I'm still guessing fuel delivery including maybe clogged injectors, or throttle position sensor, I just don't know how to confirm or deny that

Is there any good way to clean injectors and make sure there clean?

Whiskey

[Corollaczy]

I had a prob like this not too long ago but mine would be the first time I tried to accelerate out of the driveway once starting the car it just completely bogged down. It ended up being the MAF sensor. But no one could tell me what it was before it got really bad and the CEL came on

[jmk1977]

yeah, could try o2 sensor.

there should be one on your exhaust manifold as well.

Maybe one went bad?

possible grounding out on your ignition only on occasion? or maybe an injector is grounding out on occasion?

[Whiskey]

The 02 sensor is brand new - I had a bad fuel economy problem and I replaced that in hopes of fixing it.

I was able to take it out for a 100 mile freeway drive and get 36 MPG - so I called it fixed, but now I'm thinking it's not.

Unfortunately I don't have a MAF sensor, only a MAP sensor - and those can't really be cleaned.

It's possible that things are grounding out - but I've inspected the wiring and all that pretty carefully and it all seems good.

I pulled the efi fuse so that I can reset the computer because you never know. Tonight I'll get some tools so that I can test fuel pressure.

Whiskey

[Whiskey]

Hey,.. does anyone know if the rubber fuel line under the hood can be removed? I know the part on the firewall can be disconnected,.. but is that round swivel thing on the engine side a connector?

Thanks,
Whiskey

[jmk1977]

I had an injector grounding out on a mudding vehicle we have and it shorted the electrical when it would hit.

popped the hood because it wouldn't start and a wire was bright red almost white, very obvious scorching so if you cant see anything similar then probably not a short.

Hopefully the reset did you some good.

[Whiskey]

The Reset didn't help - the car was actually acting up all the way home today which is kindof a first, usually it's much more intermittent than that.

So! I checked the fuel pressure. 45 - 50 loading the enigne didn't make it drop much, looks good.

I checked fuel flow. It really squirted out of there. Check!

I checked the TPS - even climb and decline in the ohm reading, no jumps anywhere perfectly smooth. That sounds good.

I unplugged the MAP and verfied that the symptoms remined so that kinda rules that out.

Idle air thing is ruled out because it idles fine.

Plugs are new, and wires are 30K old, but I don't see arching anywhere. I couldn't find any trace of vacuum leak.

I tested the coil on every injector, they were fine.

So finally I put some super concentrated fuel injector cleaner into the injectors - let that soak, then put enough cleaner to treat 20 gallons of fuel, into 5 gallons - drove the car around like it was a race car for 20 miles and by the end of it there were no bogging issues.

However;
It's really intermittent, so I won't know if it's gone for sure for another week.

I was considering just replacing all the injectors because they do have 200K on them, and it has to be more effective than some injector cleaner,.. but then I learned that injectors are $250 EACH. Ouch.

Whiskey
P.S. If you didn't at least chuckle at my fuel volume test result, I can't help you