My Engine Has a Miss (420a) on idle.

[ryd0rz]

Car: 1995 RS Eclipse 120k miles

My car has a very rough idle, so I upped the rpm's on idle so my car wouldnt die at stop lights.

Is it possible that the problem with my car is that it has the wrong Computer in it? I know alot of mechanics and I have gotten them to hook up the car to a diagnostic computer to see what the problem was and they said that the diagnostic computer was not talking to the car's computer.

Other mechanics have told me it was the injectors or somthing was wrong with the ignition.

When I purchased the car it came with an additional computer in the trunk... I don't know what computer is in the trunk, and I dont know what computer is in the car currently. Is there any way to figure out which one is the correct computer for my car?

I am sketchy on wheither or not to swap out the computer... it could really mess up the car if I did.

Everything else on the car runs great except a loud shreiking noise between 20 and 40 mph... Some people have told me that this is a air intake problem.

Thanks,
Alex

 

[Fabian972]

Car: 1995 RS Eclipse 120k miles

My car has a very rough idle, so I upped the rpm's on idle so my car wouldnt die at stop lights.

Is it possible that the problem with my car is that it has the wrong Computer in it? I know alot of mechanics and I have gotten them to hook up the car to a diagnostic computer to see what the problem was and they said that the diagnostic computer was not talking to the car's computer.

Other mechanics have told me it was the injectors or somthing was wrong with the ignition.

When I purchased the car it came with an additional computer in the trunk... I don't know what computer is in the trunk, and I dont know what computer is in the car currently. Is there any way to figure out which one is the correct computer for my car?

I am sketchy on wheither or not to swap out the computer... it could really mess up the car if I did.

Everything else on the car runs great except a loud shreiking noise between 20 and 40 mph... Some people have told me that this is a air intake problem.

Thanks,
Alex

Idle off i would recommend checking your spark plugs also vaccum leaks losse sensors is the check engine light on?

 

[DSMcrazy3]

Get pictures of the two computers you have. ECU's in 95's are notorious for going out, and along the way they will cause many problems much like what you're describing. It happened to me, I didn't find out the ECU was the cause of all my problems until it went out and I replaced it with a better one. Yours might have been replaced with another faulty ECU, which is why you have 2 now.

 

[ryd0rz]

I have already changed the plugs and wires, checked the coil pack, and no the check engine light is not on.

My friend (who is a mechanic) also just took a look at it today and said that the throttle body was sticking... could that be the problem?


i'll post pics of the ecu's.


-Alex

 

[dr1665]

My friend (who is a mechanic) also just took a look at it today and said that the throttle body was sticking... could that be the problem?

Yes. Then again, it could also be that your IAC is failing. The ECU will control the IAC to allow air past the throttle plate at idle to maintain engine speed. In fact, the ECU also uses the IAC to test other systems in the car.

If you have verified that your vac lines are all legit, take a peek under the upper radiator hose and tell us how the two sensors on the front of the water neck look. The CLT is notorious for causing mysterious idle issues. If the ECU thinks it's -46* outside, it's going to alter fuel delivery accordingly. Just a thought.

As for the shrieking from 20-40mph, that ain't right. When you say "20-40mph," do you mean to say that it's vehicle speed-related, rather than engine speed-related? That is, does the sound happen between those speeds regardless of what gear you are in? Could you be coasting from 40-20 and still hear it? That wouldn't make much sense to me, but stranger things have happened.

I'd get back out there and try to determine when this noise ocurrs. I want to say it's a loose belt, but I don't have enough information to make a call yet.

EDIT:
You might also check out Indystars.org. They are an Indiana DSM community with a lot of members. I even know a couple 2GNT guys out your way that could likely give you a better idea in person.