First time posting, and yes, I have read thoroughly through the threads about similar problems.

I have a 95 eclipse rs that intermittently starts, and most likely unrelated, sometimes revs up high with the slightest touch of the gas (upwards to 3k) yet at times responds the way its supposed to be (tap revs up a bit on the tach).

STARTING PROBLEM: Sometimes it will turn over instantly. At other times, regardless of weather, it will just crank but not turn over until I give it a couple more tries. I have tested the battery, alternator, and starter and all turned out fine. I have replaced the spark plugs as well.

REVVING PROBLEM: As mentioned above, sometimes a tap will cause the tach to skyrocket in rpms, with a very slow return rate of down-revving(or whatever it is called). Sometimes it will respond what seems to be correct with the slightest of throttle response, along with quick "down-revving" back to correct idle. I have cleaned the IAC (if that helps in any way). I have made sure the contacts to the battery are flush, and I am suspecting perhaps a bad ignition coil or coilpack(which from researching here may be the problem). Will the TPS affect this in any way? If so, how can I test the TPS with a standard multimeter?

Nothing in either seem to be consistent to weather/environment. No codes are being thrown as well. Considering that these two problems may be related or unrelated, what may be the cause of either/both?

Please help! Thanks in advance.

BTW, here is the ride...

Your rev issue is probably vacuum related. Check all your Vac lines.
Do you mean the engine will sometimes turn and not fire? If so it could be an assortment of things. I'd try to start narrowing it to fuel or spark and we can go from there.

Originally posted by ThePerfectShift
Your rev issue is probably vacuum related. Check all your Vac lines. Do you mean the engine will sometimes turn and not fire? If so it could be an assortment of things. I'd try to start narrowing it to fuel or spark and we can go from there.

Thanks for the quick reply. A visual check on the vacuum lines shows nothing out of the ordinary. How can I test out the lines more thoroughly? I am inexperienced in that area.

Yes, sometimes the egine with sometimes turn and not fire. If in fact the problem is fuel related, such as the fuel filter, is there a simple way of seeing if the fuel filter needs replacement? Spark plugs have been changed out, but not the coilpack or wires. i tested the resistance on the wires and all seems within spec for the mfg.

The main thing that puzzles me is the inconsistency of the starting and revving issues. I can't find any pattern! Thanks again.

Thanks for the quick reply. A visual check on the vacuum lines shows nothing out of the ordinary. How can I test out the lines more thoroughly? I am inexperienced in that area. Yes, sometimes the egine with sometimes turn and not fire. If in fact the problem is fuel related, such as the fuel filter, is there a simple way of seeing if the fuel filter needs replacement? Spark plugs have been changed out, but not the coilpack or wires. i tested the resistance on the wires and all seems within spec for the mfg. The main thing that puzzles me is the inconsistency of the starting and revving issues. I can't find any pattern! Thanks again.


There is a canister under the passenger headlight behind the bumper that vacuum lines go to. Possibly a cracked one there. There is no visual way to tell if the fuel filter needs to be replaced but you can check your fuel pressure to see if it is getting the right fuel pressure. If its not, then possibly the fuel filter is clogged. That may be your starting problem. As for the reving problem, possibly your TPS or maybe your Idle air control motor, the sensor on the throttle body under the TPS. You can test the IAC motor with a multimeter and setting it to ohms. Put the leads on pins 1 and 4 on the sensors and then 2 and 3 pins. If both readings are between 38 and 53 ohms then it is fine. If not, replace it. Rockauto.com has them much cheaper than any other place if you need one.

It may be a bit early to consider this one, but it could also be the ECU. Since you have a 95, you have the short square ECU that is known to fail. I just replaced that ECU in my car. It started having the same symptoms, and turned into I would be driving and the car would just stall like I turned the key. Replaced the ECU and it runs like new.

hmmm..... didn't think about that possibility but I just know that i would check all of the little things before i go spending money on a new ECU.

For the start issue - maybe change out your ASD relay - they're just plain old accessory relays located on the driver's side firewall. They can get finicky. Otherwise I'd maybe try pulling your plugs when it's just turnin and not starting, see what they look like. may give you some insight to if you're not getting spark, or if it's flooding, with a bad injector leaking or something like that.

Start by fixing your coolant problem first. The coolant temp sensor is not getting the proper information (that's if its still good) and that can cause crazy problems like you mention.

Not saying its not any of the other things mentioned, just saying that you need to fix that problem first.

Coolant temp sensor can definitely cause gremlins.

To check for vac leaks, if you're a smoker, fire up a ciggie and move it near vacuum connections. If there's a vac leak, the smoke will be pulled towards it. Beyond that, you can also try spraying carb cleaner along seams/gasket areas. If the idle changes when you spray somewhere, it's a good chance there's a leak there.