a problem i cant solve no mater wat throw at it

[jimmy[the]gent]

89 toyota tercell 4cyl automatic

everytime i go steadily faster then 80km/h the car starts givin a litle rock back and forth then its like the more gas i give it the worse it gets and starts drasticaly slowing down so i have to get off the gas and slow down i thought it was an exhaust leak until today when i looked for one and found nothing (pos car drives fine under 80 km/h though]

recently changed the oil, water pump, spark plugs, distributor cap, exhaust manifold to exhaust pipe gasket, belts and a while ago the fuel filter and air filter

WAT COULD IT BE?


i hate my pos car

[ne0c0de]

Is it a injector or carbureted engine?

Did you check the status of your spark plugs when you were changing them?

If it is a carburetor then check the Power valve otherwise your fuel Pump. Maybe it doesnt give enough fuel.

Also check your timing if they are too advanced. And also your plug wires.

[MagicRat]

If its '89 its EFI.
It sounds like a fuel delivery problem to me, so its the fuel pump or the fuel filter.
If the fuel filter has plugged up this quickly, the inside of the tank may be rusty. The rust is clogging the filter too quickly.

[76455Firebird]

sounds like you might have some really worn motor mounts. maybe check the condition of those. They could be seriously compressed or decomposing due to age and weather.

[stfuad]

I'd take the plunge and get it checked by a mechanic. It could be anything. Does it sound like it's only running on [1-3] cylinder(s)? The car might be running in safe(limp) mode if it's EFI. Does the car use a Check system or something like OBD1?

Was the car doing this before you did the part replacements?

[curtis73]

The rocking back and forth I assume is the engine cutting out and giving you power, then no power, then power...

Since you just replaced the fuel filter, look there first. Its quite possible that you sucked a piece of dirt into an injector, the fuel pressure regulator, or the fuel rail. Its also possible that your fuel pump is dying but you've overlooked it since more recent modifications lead you to think that they are at fault.

Fuel demand is directly proportional to how much of your right foot is used. Try this. From a stand-still, floor it. How fast do you get before the problem happens? You mentioned that the problem happens at 80kmh and gets worse if you add more "foot."

If you are able, do the tests yourself, but this sounds like a classic fuel supply problem. Piece of dirt somwhere, bad fuel pump, bad fuel pressure regulator, leaky line... something is causing the injectors to not get the pressure or volume of fuel that they need. Let us know what you find out. As much as we educate you on this, it educates me/us knowing that we were wrong/right.

[jimmy[the]gent]

thanks for alot for the replies

i think u guys might be right about it being the fuel system the only thing i have ever done to it is replace the fuel filter

the car gets the absolute worst acceleration ever when i just floor it off the start.

the car is carburated and if i was to start looking for a problem in the fuel system where would i start besides a new fuel filter il admit it now i dont know shit all about this cars fuel system but am open to sudgestions..

[jimmy[the]gent]

Originally Posted by ne0c0de

Is it a injector or carbureted engine?

Did you check the status of your spark plugs when you were changing them?

If it is a carburetor then check the Power valve otherwise your fuel Pump. Maybe it doesnt give enough fuel.

Also check your timing if they are too advanced. And also your plug wires.

yea i cheked the status of my spark plugs when i changed them they where terrible no oil on them just grossly overheated and worn they where in my car for bout a year

thought i solved that problem by changing the thermostat and water pump cause it dont overheat no more..

and yea its carburated

[benchtest]

Jimmy, Does this happen all the time or just sometimes? What is the air temperature when this happens?

[jimmy[the]gent]

thats a really good question i notice that this only happens at night or really early in the morning like when its cold out and u can see your breath

thats why i thought it was an exhuast leak cause i thought that cold air was getting back into the engine and making it jerk

my pos car never pisses me off so much on sunny days lol

[benchtest]

Jimmy, Does it run fine at idle, drive fine above 45 deg. F (7 C) or so, but when the temp is between 35 and 45 F, it does the following: slows down while driving and goes even slower if you press the gas, black smoke comes out the exhaust, runs very rough, etc., and then if you pull over for a couple minutes it takes off fine again for a little while and then repeats. Does that sound right? More specific details would also help.

[jimmy[the]gent]

it doesnt idle good wen i first start it in the mornings i kind of have to give it gas so it doesnt stall but after a while it idles fine after it warms up a bit

never really seen my car smoke too badly... start up i see a bit of smoke come out but right after that its normal

yea its worse when the wheather is cold but i still think its the fuel system more specificaly i fear its the fuel pump

[benchtest]

Jimmy, Drivability is about 70% what you see and hear, so online diagnostics is difficult at best. However, what you have described sounds a lot like carburetor icing. There may be other issues with your vehicle, but I would look at your heated air system also. If you are not familiar with that, it's the system that provides warm air to the carb. in cold weather. There will be a pipe that leads to the air cleaner snorkel from a heat stove on the exhaust manifold. The door on the snorkel needs to be operational also, be it bi-metallic or vacuum operated. If any part is missing, replace it. Sorry for the re-hash if you're familiar with it.

[jimmy[the]gent]

carbureator icing huh never heard of that before....
didnt now about that litle stove thing that heats up the carbriurator either guess il check that out thanks