I have a 1987 Nissan Maxima (standard transmission). About a month ago, I had the clutch replaced and while my car was in the shop, the mechanic told me that the throttle position switch was bad and needed to be replaced. I hadn't noticed any idling problems, but he convinced me and they replaced it. Now that it's starting to get a bit warmer, I've been noticing that my car has been idling high (usually 1000-1500 rpm, when it had been at about 700 rpm before) and occasionally I'll step down on the accelerator and it will lag before I start accelerating. My boyfriend thought that the new throttle position switch that had been installed could be bad...Then we were looking at my Haynes manual and it says that the throttle position switch for 1987 Maximas is different from other mid/late 1980's model Maximas and that to test continuity you use the bottom and middle connectors, rather than the middle and top connectors, so he thought that the garage could have put the wrong type in. I'm wondering whether or not the throttle position switch is different for the 1987 Maxima or if the Haynes manual is incorrect. If anyone has any insight about this, I would love to hear it before I order another switch or complain to the garage.

 

There shouldn't be much difference, if any at all between the 85-88 maxima's. What you really need to do is pull out the ECU from under the passenger seat and check to see if it's giving you an error code. The steps are outline in the Chilton's manual (the haynes one is inaccurate). I would start there first. As for the higher idle, this could because you have accessories running. Our cars have a build in device that raises the idle automatically to the range your said when you have things like your headlights, climate controls, or defogger on. That should be normal. If its like that with everything off, then you need to reset idle. You can do this by getting the motor to normal temperature, then shutting down the motor, disconnecting the F.I.C.D. harness (when looking at the motor, its on the back left side of the intake manifold) and then adjusting the idle appropriately. Then you shut off the motor, reconnect the harness and you should be done. Refer to the haynes/chilton manual for the exact procedure. Hope this helps you out.

S

 

As Sarin said, you probably need to adjust your idle, that should clear up your high idle. The procedures should be listed in your Haynes book. Most likely someone set the idle up higher to compensate for the colder air because your air regulator is broken. Don't worry about the air regulator, almost everyone who owns a 2nd gen has a broken air regulator. All it does is boost the air going into the engine when it's cold outside to keep the idle high. Otherwise, you get heistation when you first start up and the engine runs overly rich when it's cold outside.

It certainly is possible that the throttle valve switch is bad which is why your engine is idling higher, because the swtich is not making contact with the the idle contact point, but I doubt that you have the wrong one, I don't think the car would run if the connectors didn't match up.

As for the heistation, there are a lot of things that could cause that. It could be that you need a tune up, a new O2 sensor, a new fuel and/or air filter, your catalytic converter or muffler may be clogged, a sensor is about to fail, a bad EGR valve, a bad fuel pressure regulator, and the list goes on and on...

Do as Sarin said and check the ECU codes, that could help you narrow down the problem. It would also help if you knew how long ago all of the maintenance has been done to the vehicle. For example, copper spark plugs normally last 30K miles, as does the O2 sensor and fuel and air filters. Platinum tip plugs last about 100K miles. Wires and the cap and rotor could last between 60-100K miles. A converter and muffler normally last 100-150K miles.

So, if you know how long ago this stuff has been replaced, it could help you narrow down why your car is hesitating.

-C-

 

Thanks for the suggestions. Is there a way to find out what the correct ECU codes are without buying the Chiltons book? I spent some time yesterday going to book stores, auto stores, and the library and no one had it.

I guess I know what I'll be doing this weekend. :-)

 

Go to the 2nd Gen Club (listed in my sig). Sign up for a membership. Then go to the LINKS section. There's a link to a site that has how to diagnose the ECU for our cars and lists the codes. I believe the link is under General Information.

-C-