Idling Low

Bradt · Nov 1, 2004

I replaced my fuel filter this weekend. The thing was so clogged I could barely blow through it. That took care of the sputtering problem I had. Now there's a new problem.

When I crank the Bronco it will idle strangely. The RPMs go up to 1500, then back to about 500, and back and forth. Sometimes it cuts off. If I tap the gas and get the RPMs up to about 2000 or so it will drop back to 1000 and idle steadily there after that. Any ideas what I should check out first?

Brad

BigNasty · Nov 1, 2004

If carburated, I would start with the choke adjustment.

Bradt · Nov 1, 2004

It's fuel injected.

Bradt · Nov 2, 2004

I got some carb cleaner and shot it down in the throttle to flush everything out. It seems to have helped quite a bit. Now the RPMs hit about 2000 on ignition. That seems about right. Then it bounces down to about 500, and up to 1000, down to 700, back up, and so on until it levels off.

I'm considering opening up the throttle body and soaking it down with carb cleaner, and checking the PCV valve next. The hose leading to the Throttle was so dry-rotted it was just flaking off in my hand as I tried to replace it, so I'm thinking there may be some bigger chunks that didn't flush out. Sound like the right way to go?

Brad

fbrown3 · Nov 2, 2004

Not sure if this will help, but I had one do a similar thing and it turned out to be the TPS(throtle position sensor) was out of wack.

Justshootme84 · Nov 3, 2004

That's right, it's the TPS causing the problem. You can check the voltage with a meter, or just replace it. Not too costly or hard to do.

mustangman65_79 · Nov 5, 2004

Justshootme84 said:
That's right, it's the TPS causing the problem. You can check the voltage with a meter, or just replace it. Not too costly or hard to do.

not just yet, could be the engine coolent temp sensor for the engine. Will cuase the problems above, and die every once in a while too.

Bull · Nov 5, 2004

I'd have to agree with the TPS, it will do exactly what your describing when it's failing. Mine did on my 91 anyway.

Bradt · Nov 5, 2004

We finally got a good sunny day again, so I took off the throttle, cleaned off the valves. Pulled pretty much everything out and cleaned off a nice thick film of stuff (Some of it was almost like charcoal), and ran about half a can of carb cleaner through. Seems to have dome the trick. We'll see though. This thing has had a way of making me think I'm done just long enough to get me comfortable.

Brad