some one help me PLEASE!!!!!!!!!!!IM DESPERATE

[86300zx4+4]

My 1986 300 ZX 2+2 is in some kinda of safe mode or some thing. It keeps the engine from going over 2000 rpms. At 2000 rpms it shuts of the fuel to the engine and then after going back down to 1500 rpms it resupplies the with fuel. Basically making it red line at 2000 rpms. It happens on and off from day to day like its a bad electrical connection. When it does this the over drive light and overdrive function stop working as well as part of the safe mode. Please help me I have done so much to this car and i really need some help on this one.

[Fahaka]

sounds like the mafs is disconnected...

[86300zx4+4]

What does that mean?

[86300zx4+4]

I have heard that before but I don't know what that means.

[Fahaka]

mass airflow sensor...you will find it upstream of the throttle before the air filter. it will have a harness connector with four wires (I think). If they are all connected it could be a bad mafs (mass airflow sensor).

[86300zx4+4]

I have un plugged that before and it made my car run really bad and die so i thought that seeing how it was effecting something it was working. is this the usual case?

[Fahaka]

What?

[86300zx4+4]

I have unpluged the air flow sensor before to see if would effect something and my car ran noticably worse and then died. If my air flow sensor had not been working in the first place then it would seem that unplugging it would have no effect.

[Fahaka]

the computer will go into safe mode if the mafs is disconnected, preventing it from revving past a preset rpm.

it could be a poor electrical connection, or a bad mafs.

does it idle ok?

[86300zx4+4]

Yes it idles fine. I suppose it could only partly be broken but how do i make sure and how sure are you about your diagnosis. I may act on it buy a new mafs solely on your diagnosis.

[86300zx4+4]

and Im not exactly a rich person Ive just been working on this so long and Im ready for it to be fixed.

[86300zx4+4]

I have been dealing with this problem for years now and have worked on it between my other projects on the car. Besides the engine pull I have collectivly probably put more hours in to this than anything else.

[Fahaka]

have you checked the ecu for codes?

[86300zx4+4]

yes but im not sure if i did the procedure right. Its really hard to do that by your self. but i doubt that things answers as well and i have switched it out too.

[Fahaka]

Get an fsm, follow the procedure to check engine codes and see what codes it is throwing. Then get back to us.

[86300zx4+4]

what is an fsm. well any how I pulled the mafs( which wasn't easy) and tested it and it passed. I guess Im going to check the harness next and then Im going to get some one to help me run the diagnostic again. I think its the crank angle sensor because thats what it said before. That is what I am fearing most though because I priced one a while back around $400 at the cheepest and I don't have that kind of money. But that was a while back so I might be wrong...

[Fahaka]

fsm=factory service manual. There is a way to check the computer to see if it is throwing a code. Or you can take it to a shop and have them hook it up to a consult to see if it is throwing a code. Either way I'd start there...

[sharjt]

Download the FSM from "http://carfiche.com/manuals022/cars/" and READ!!!

Also autozone will hook your car up to a computer and check your codes for free.

How did you pull the mafs to test it? It shouldn't be that hard at all.

as for how he thinks it's the Mafs, probably the same way I think it's the Mafs. It's happened to us and lots of other people and we have lots of experiance with these cars. Now that being said this a public forum and none of us are professional mechanics so we could all be full of crap. I suggest buying a mafs and if it doesn't fix it return it (that's why you should keep the reciept).

If autozone says its the crank angle sensor and they cost that much from themcheck the junk yards.