Odd Problem.. runs good; rpms inconsistant; cuts off

I have a very odd problem with my 96 eclipse RS (167k miles, no mods just intake). I've had it for many years. When I am going down the highway the cars rpm's will drop all the way down and then jump back up. When this happens I lose power to the gas pedal. Most of the time when the rpms drop then it will pop back up; but once or twice it has totally cut off. It has started to get worse here lately. Sometimes when driving 35-40mph it will do the same thing but since it does not have enough gas flow (i am guessing) it will jerk. If I am going slower in town the car will jerk. If I am stopped at a red light and this happens the car will cut off, but it will start back up after the first try, sometimes after a crank or two. There is no CEL on and doesn't seem like it is going to give one for this problem. Plugs and Wires are new, EGR valve replaced after a CEL for it (after this problem started occurring). Some drives (20-30minutes) it does not have this problem, but most of the time it happens.

I was wondering if anyone had any ideas of what it could be? I'd really hate to take it to the dealership.

try fuel filter if you believe its not getting fuel

The fuel filter has been changed recently and also the fuel pump ( about 3-4 months ago for the fuel pump).

Did you check the PCV valve? A simple couple dollars for it and a few minutes to change it out. Even if that doesn't fix it, its a good idea to change it with your mileage as it is.

I am replacing the PCV valve and hoses tomorrow morning. I got home late tonight. I will let you know if it helps tomorrow afternoon or the next day.

I replaced the PCV Valve which it seems to help the problem or atleast it hasnt been losing power/gas as bad. The problem still exists though. Any other ideas?

I replaced the PCV Valve which it seems to help the problem or atleast it hasnt been losing power/gas as bad. The problem still exists though. Any other ideas?
Hmmm... Well we are on the right track at least... Have you given it a well rounded tuneup lately? Plugs, wires, air filter, fuel filter, etc?

Yes the plugs and wires were changed not too long ago (about 2 months I think it was). The air filter is clean, fuel filter changed also. It seems to act up most of the time going up this one hill coming home. I drive about 20-25 minutes before getting to the hill. Other times it will lose power for a second and then jump back up while going down the road regularly but it is not consistant.

Have you tested your coil to make sure its not going bad?

Loose connector/wire somewhere or the ECU.

Well I still have not solved the problem. I've just been dealing with it because it is slightly random and I have another car that i can drive. I've noticed something else about the problem here lately. Going down the highway if i loose power/gas to the car I can let off the gas peddle completely and press back on it and it will regain power. The coil pack went bad about a year ago and was replaced. The problem seems to happen more often after the car has warmed up. The other day from a cold crank I went down the driveway (about 400-500ft) and the whole way down it without pressing the gas the rpms jumped up and went down to almost nothing (while getting near nothing it rattled but i think it was starving for gas) and then back up about 3 or 4 times so i decided to park it and drive the other car. That was the first time that this has happened. (this makes me think the Throttle Positioning Sensor might be going out but i'm not sure). If at a red light it will just cut off. The problem mostly happens on the highway as described. Thanks for any suggestions.

I think i know what your talking about, I had the same problem, but with a diffrent car, while not exactly the same model or year, it was still a dsm. My 93 lebaron le would do this, tried to reaplce some wierd thing under the the rotor, but that didnt help, replaced the fuel filter also, but that didnt help. The problem got worse n worse. Finally my mechanic ruled it out as a bad/going bad fuel pump, and computer. Im not sure what computer, ill look for the bill and let ya know.

Yeah I have also thought about the fuel pump. I'm not too sure about that though. I know they can do some crazy things but seeings i can let off the gas and press back on and then get power/fuel makes me unsure of the fuel pump.

Throttle Positioning Sensor is 115$ from dealership.
Fuel Pump (not from dealer) is around 130$.

I'd rather not guess and replace parts but it seems that is what i might have to do.

My problem was, while driving around, the cars rpms would drop to zero on the tach. then come back up again, then go down and the car would "prepare to stall" as i called it. What i would have to do, is pump the gas to keep it going, it would just drop to zero, come back up, drop to zero, and so on while I was pumping the gas, it would slow down slowly, and eventually come to a dead stop. If i press the peddle to the floor, its would just die, and all the light on the dash would come on cause the car stalles on me.

When i come to start it back up, it would idle normally for a sec or two, and then die. Id have to wait a good ten minutes to start it again and get it going. Some times id just have to start it right back up, and it would be fine. My car was a 93 lebaron le, with teh 2.5 sohc motor, and auto 3speed?

The things the mechanic replaced were the fuel pump, the computer, and something that was screwing up the fuel gauge on the dash, sending unit? and an oil change. (the fuel filter, and the other weird part were replaced a few days before)

Some people said it was a vacuum leak, egr going bad, sludge in the motor, and some people said it was that I drive... i cant find the bill, ill just go back up to the garage and get another one, and let u know of any other details.

I hope this helps.

Ok. Mine is doing about the same thing but not near as bad. I've had it to a local garage for a few days and it would not act up for them. (what a coincidence). If mine dies at a red light it will crank right back up. Highway I have to let off gas and press back on. I think I will start by replacing the fuel pump. They can do some crazy things.

lol, i hear ya, when i took mine in to get checked the first time, I told em to test it, the dude took it for 3 runs on the high way, and it didn't nothing.

Thats when every one came up with the solution that it was just the way I drive since I had a few other people drive it also.

I don't know if there is a way to test teh fuel pump, but if there is, I'd check it out if i where you. I hated replacing parts that didn't need replacing on that car.

Yeah that is what i am trying to avoid.