strange ranger behaviour

[dark_flame221]

So, i got this 1990 xlt 4wd ext cab manual Ranger, that is older than me, since about 18 months.

When i start it, hot or cold it will idle around 1k-1200 rpm and will take like 5 minute to resume to normal idle speed wich is about 750 rpm and when he's at it, he will hip cup = rpm will drop quickly to 600rpm and go back and forth from 600 to 750 rpm rapidly
SOMETIME, he will also make the rpm decrease slowly as i try to upshift

what is he suffering from ?

Now that it tuffed me 1 year w/o investing any money beside oïl change. I'm gonna give it a second life bought 4 new shock 2 coil spring and the leaf spring are on there way.

 

[FritzTKatt]

Should've thrown money at the motor before you shelled out for the suspension.

Check out all the basics. And vacuum leaks.

 

[stegomon]

I think there is a sensor on the top half casting of the intake. I think that is the imtake air temp sensor....I think. Well my father changed it on his now mine bronco 2. It solved the problem of what sounds simalor to your situation. But like fritz said. Check the basics. Don't throw parts at it. You could always get a coputer reader from napa for a few pounds and see what the trucks is saying

 

[FritzTKatt]

Way too many things can cause those problems. That's why the basics are so important.

I had a similar problem, and was throwing parts at it. When I was up on top of it, looking down, I noticed a vacuum tube had a crack near the boot. Not noticeable from normal point of view, but a dab of glue that dries flexible fixed it like new. MAF sensor made another drastic change with just a cleaning. Filters... seafoam... it's not related to your issue, but get under there with a greasegun and hit all those zerks. Pull electrical connections, clean them, and a dab of dielectric grease on the pins... Preventative Maintenance Checks/Services will make or break your truck.

So any way, go crazy with the small stuff. If nothing else it'll run better, enough to help identify the underlying issue, and when it's all said and done you don't have to worry about the small stuff for the next 3k miles.

 

[lil_Blue_Ford]

Every time I get a new-to-me vehicle, I start by doing a complete tune-up ASAP. Plugs, wires, cap and rotor (as required), fuel filter, oil change, PCV valve. While I'm crawling all over the engine changing all that stuff, I go looking for vacuum leaks, oil leaks and other problems.

You might want to think about pulling the IAC (Idle Air Control) off the intake and clean any gunk out of it with brake cleaner or carb cleaner. When they get gunked up they can do some not-so-funny things to the idle.

 

[FritzTKatt]

I like seafoam for things like that. Cleans IAC's, throttle bodies, PCV valves, carbon buildup in the motor, injectors, carb jets, just about everything.

MAF cleaner on the electrical components. If it's really cold though, you have to go easy or it will just puddle inside the connection. (Definitely not recommending this, but I had to burn it off by lighting it with my cigarette lighter before)

 

[lil_Blue_Ford]

I like seafoam for things like that. Cleans IAC's, throttle bodies, PCV valves, carbon buildup in the motor, injectors, carb jets, just about everything.

MAF cleaner on the electrical components. If it's really cold though, you have to go easy or it will just puddle inside the connection. (Definitely not recommending this, but I had to burn it off by lighting it with my cigarette lighter before)

Cleaning the PCV valve isn't always enough. I did that with a BII I had. I actually cleaned it twice and was still getting a little oil out of the exhaust. Put a new PCV valve in and the problem went away. I guess the spring inside it was just getting too weak.

 

[dark_flame221]

my problem would be a mix of vacuum leaks and carbon buildup in the the maf sensor?. I will check the IAT sensor and pcv valve...

Vacuum leak will make my idle rpm go up and faulty pcv valve will make my idle to hip cup right ?

just trying to see what solution will solve wich problem...

Edit : i've got the 2.9 does this change anything ? does it has all the previous sensor ?

 

[dark_flame221]

well after putting new coils springs front shocks and new poly bushing almost every where = cab mounts sway bar, ect.!.... (had to disconnect the battery for 2 days)

started it up and BANG !!!!!!!!!! it started running freakingly fine.... :O