My car has been having issues lately. Basicly what happens is when I start it up and drive for a few minutes the engine begins to intermitantly lose power through out the whole rpm range, its a jerky switch between full power and rough low power as if I'm flipping a power switch to one of the rotors on and off. Finally it will just run like crap, making very little power, unable to hold an idle and sounding very strange (one rotor mabey). If I park it and let it sit for more then 15 minuets it will run like nothing happened until the problem comes back. Also for the past few months my car wouldn't idle when cold (related problem?) my car is an 88 na fc, I have no cats or emissions, full RB exhaust with header, safc, aux port mod. Any input or ideas would be appreciated.

 

anyone? any ideas?

 

I would check the water thermo sensor located on the rear of the waterpump housing.... sensor controls fuel and can lead to a rough ride or as you are saying jerky ride also..the sensor will cut fuel to the car when the engine reaches normal operating temperature.... otherwise when you start up the engine will run fine when it's cold.... the moment you get near normal operating temp it starts up....

quick check is to disconnect the sensor clip and start up the car normally and see if it runs fine without the sensor clip attached... if it's that then you have your culprit...motor will run just fine without the sensor attached..

this is what comes to mind on the issue you posted....

 

Tried it, no luck. Still wound up limping home on the free way at 40mph with the hazzards on. I'm baffled by this I checked and spark is fine. Are there any other retarded little sensors that could cause this?

 

bump

 

My first choice would be to pull the spark plugs and have a look see at the color.

 

I am having a simular problem, my car has pretty consistant power until about 4000 - 5000RPM, themm all of the sudden power cuts out, if i let off the gas a touch, it will come back, then cut out.

If i keep it floored it just gets to a point and stops reving and has no power. It doesn't bounce the RPM's like something is cutting out all together it just stops having power.

If i let off the gas a little the power will come back and then i will have to readjust my foot to get it back again ect.

I am also lost as to what is causing this.

 

Not idling when cold could be a voltage issue. Alt going bad or something drawing lots electric. causing your TPS to fail killing your idle.

Your intermittent power loss could be your main relay. Open it and check it if you havent already.

 

well I checked the main relay and plugs, both are fine, I replaced the tps, fuel pump, and crank angle sensor and still nothing! Tommarow I'm going to replace the fuel pressure regulator and see where that gets me. I also checked to see if all 4 plugs are getting spark when its running crappy and they are. If the new regulator doesn't work, then next on my list is new injectors and ecu.

 

check the alternator wiring.make sure that it is clean and corrosion free..along with the Battery connections..In a way it sounds like it is Loose...another thing would be to clean up the grounds on Both coils.If they are dirty then you could get power loss off and on also.I'm just Pulling stuff off the Top of my head.But it is stuff that shouldn't be Overlooked..another Thing would be a Bad fuel filter,and a clogged fuel sock.

 

Check your tps...

 

It might be a bad fuel filter. When the car is shut off the fuel runs back to the tank and maybe also all that junk thats not getting through the fuel filter. Then when the car is running and fuel is flowing it gets clogged again.

 

It doesn't work like that, the pressure line always has pressure. it comes from the tank to the fuel rails.

The the fuel pressure regulator sends anything over XX psi (mid 30's) back to the tank via another hose.

So if the filter is clogged it is clogged. but it won't get uncloged and then reclogged.

 

Update, lifes been kinda busy lately so I just let the car sit. Anyways I checked my timing while it was running badly I noticed it's advanced, way advanced. when its running smoothly the timing is dead on, then it abruptly advances and my engine runs like crap. Any ideas what the hell is happening?

 

Could be your TPS sensor is the problem. If it is not working the ECU thinks you are at WOT and thus advances the timing.