Working on a 98 with 223k miles.
I noticed last week the following. The car has a button for cruise control near the drivers side door panel. It isn't lighting up when pressed nor is the cruise control light on the dash. However, when I'm driving and press the gas to 15 miles an hour the car will just sit at fifteen miles an hour (as if the cruise control was on) til I use the brakes to slow the can down. The brake doesn't seem to disengage the cruise control but it will stop the car. In the three times I've driven the car this week, it did this twice on starting up. The first time the behavior stopped after I drove around. The second time it stopped exhibiting this behavior and then it came back later as I was driving.

As far as I can tell the car is only doing this in gears 1-3 (in fourth gear it will slow down normally if I let off the gas). It seems like it is idling a little high (1200 rpm) after I start it. And it feels like when it deaccelerates out of first and second gear the car will shake a bit.

Any ideas what it could be or how to troubleshoot?

 

What rpm is the idle when the car warms up to operating temperature?

 

About the same around 1200

 

I don't think this is a cruise control issue, because I think your issues are due to the high idle.

I'd start off with the simple stuff first. Your throttle plate may be sticking partially open. Remove the snorkel from the throttle body. Clean both sides of the throttle plate with throttle body cleaner and also clean the bore of the throttle body.

 

You think it's not the cruise even if the cruise button is not lighting up when pressed? And the dashboard light for the cruise control is not coming on either? Both of those worked before.

I trust your opinion. I just want to double check before pulling the throttle body off.

 

Sorry for the newb question, but I'm curious. How are the cruise control and high idle connected? Sorry if this is elementary, I'm still learning my way around cars. Although I am some what handy, I recently made a pair of blacksmithing tongs for example.

 

I think your issue is due to a high idle and not the cruise control. It sounds like you cruise control is not working and you can troubleshoot the cruise control after you solve the idle problem.

You don't need to remove the actual throttle body. You just have to remove the rubber tube connecting the air filter box to the throttle body.

The other thing to quickly check are the 2 cables that open the throttle body (one is the cruise control and the other is the throttle cable). Both cables should have slack at the throttle body. If one is tight and opening up the throttle body, then you will need to fix that issue.

 

Thanks PA. I cleaned in the inside of the throttle body twice (and also the outside where the cables attach because it was covered in grime) but getting same issue. Though it appears that the idle is a little better (900-1000 rpm) after just starting the car.

When I start the car and leave it in park if I hit the gas very lightly the rpm will rise to 2000 or 3000 and just sit there or will rise and then slowly drop to 1500 rpm (but not 900).

If I manually open the throttle however it falls back no problem to 900.

Would you say I just need to try cleaning it again because something is sticking or would you look at something else?

 

When you said you hit the gas lightly and the RPM hangs, do you mean you're using the accelerator pedal?
Then you "manually open the throttle" meaning in the engine compartment you turn the cable-drum directly?

It's beginning to sound like the throttle cable (from the accelerator pedal to the throttle body) is gummed up or something, causing excessive friction in the cable. Or maybe it's the pivot hinge of the pedal itself? Or some carpeting getting in the way?

Try this with a helper...
Warm up the engine & have your helper in the drivers seat. You watch in the engine compartment.
Helper revs the engine - enough to get the RPM to hang up.
You should be able to see whether the cable goes slack at the throttle body or whether it's a sticky cable that doesn't allow the throttle to close quickly.

edit...
Actually, with your helper, you might not need the engine actually running. If the engine isn't running, your helper can actually floor the pedal completely, then let go. You should be able to watch the cable drum; and see whether it snaps all the way closed immediately.

 

Thanks Jim. What I was describing was just tapping on the gas pedal (tapping it and then letting off) and then the rpm would hang.

I just looked at it again. I realized that if I tap on the gas it just stays pressed down and the rpm hangs. If I pull the pedal back out or use my foot or hand to pull it back to the zero or the starting position the rpm drops to where it should be (roughly 900 rpm). That means I think that the problem is not inside the throttle body most likely?

How would I determine if its the pedal that's sticking or the cable itself? Attaching photos of the pedal here and the cable.