I have a 96 2.4l Stratus with a poor idle.

I took it to a local garage with a good reputation for diagnostics and repair.

I originally requested they perform a tune-up, check plugs, wires etc.

They said all the plugs and wires were in good condition.

Anyways, when I first got the car about a month ago it ran fine until I decided to check and see if the A/C worked. Since then it has never idled properly (always up and down). I decided to clean the throttle body with cleaner and pop some "injector cleaner" in the tank. Not long after the check engine light came on.

It was then I decided it needs a proper look at. The garage popped the car on the computer and it showed the following codes.

P0123 TPS volts hight
P1594 Charge sys high volts
P1598 A/C pressure sensor high volts

They cleared the check engine light and I`m unsure what they did but the car has idled great for over a week. But now, the poor idle has started coming back. Prior to taking the car in to the garage, the idle so far bad it would surge to over 1000rpm and drop enough to stall. It isn`t that bad - yet!

They did mention on the works order that the A/C fan is busted up and needs replacing and that could be causing these idling issues, something about it is putting on a load (or something like that). There is a rattling sound, kind of a plastic rattle coming from the engine compartment when I start up. That must be the fan they were talking about.

From the above information, can anyone give me some clues as to what may be going on?

Oh, also when I first got the car noticed the battery light coming on after ten minutes driving. Since it was taken to the garage, I haven`t seen that light since. Maybe related to all these problems?

I`m leaning toward an alternator problem, especially since at one time I was getting the battery light. But then I don`t know much!!

 

not sure about the voltage issue.
the idle problem sounds like the high idle relay. this come on when you turn on the a/c to compensate for the added load of running the a/c compressor. the compressor cycles on and off like a house a/c. it does this to keep ice from forming on the evaporatior coil in the dash. the relay will kick the engine into a higher idle (1000-1200rpm) when the compressor is on and turn off when the compressor is off (letting the car run at normal idle). the low rpm you describe sound like the a/c compressor is on and the eng computer is keeping the motor running and alowing the motor to "surge" when it shuts off (it takes the computer a few seconds).

 

I`m pretty sure that`s what the tech said. He mentioned something about the A/C was stuck on or something like that, in effect it was causing these idle surge and drop problems. He said that fan definately wants replacing, but I`m not sure what fan he was talking about. I should have asked if it was the ac/heater blower fan or the a/c fan down near the radiator. I do hear what sounds like a fan rattling and scraping under the hood area or behind the firewall area.

Is there anyway to bypass this? It`s not like I`m going to be using a/c until next summer anyways. I figured removing the belt, but of course the serpentine belt controls that and eveything else.

Thanks.

 

you could discon the low press switch, just make sure you wrap the connections to keep them clean. this will keep the compressor from coming on. you could buy a belt for your model car that does not have a/c.

the fan is under the hood, behind the rad. the unit is not very hard to change out, spend a little time searching on-line. i just replaced both of my headlight units for under $200, brand new. not a factory fit, but some sites were asking $200 for one side.

 

I`ve managed to track down a fan assembly, my local junk yard has a working one. Going to change it the end of this week.

Just a bit confused by all this however. Since I first tried switching on the a/c almost three weeks ago, I have never switched it on since. I`m just wondering why I would still be having this ac/idle problem with the a/c switched off.

With a correctly working fan, that should lower the a/c pressure and help with the idle problem.

The whole idle thing is not exact. It can idle fine for several minutes or more then the 1100rpm surge will start, then drop off to near 500rpm then will settle again at around 700rpm for a bit before starting off again with the surge and drop. It doesn`t stall, but it`s not far from it!! Kind of annoying at night with such a drop in idle, it obviously effects the lights too!

So you think this a/c problem could be causing the up and down idle?

Oh before I forget, where it the pressure switch located (the one you mentioned)?

Thanks again.