Okay so I have been driving my 92 pickup for a while and luckily it hasn't broken down or anything but I feel like it has quite a few mechanical issues that seem to be getting worse. Here are the 3 main ones that are bugging me:

First off, after warming up, the truck's idle surges when the brake is pressed down. So when I'm at a stop, the idle drops down every few seconds then comes back up. Its annoying as hell. I'm thinking this may be a vac. leak but how do you find out where its leaking??

In addition to that, it just feels like it runs pretty rough. Idk, I just came from owning a 2008 honda, so maybe I'm just not used to an older vehicle. But at the same time, I have a 1986 corolla project car and I feel like it runs way smoother than my daily driver pickup and I only drive it once a month! Also, when it starts, sometimes it just jerks the whole truck. Like it starts really really rough if that makes sense.

Finally, it also vibrates like crazy when i get up to about 50 or 55 then the vibration goes away at about 70. I know for a fact that one of my front wheel bearings is a tad loose but is there anything else that could cause this vibration that I should look at? Ball joints, tie rod ends, etc.. ?

Those are my 3 main problems at the moment. I love this truck more than anything I've owned so far, but these little things are starting to add up and really get on my nerves! So any ideas on where to start or what to do about the described problems is much appreciated. I don't have that much mechanical skill and when a problem occurs, I'm just completely lost as to where I should start! ha

 

Vibration could be an alignment as well. Does the truck pull one direction or the other?

Also i believe you idle issue you ill find is your IACV. You can try to clean it by taking off the intake hose and spraying throttle body cleaner down inside the big hole.

I will say im new at toyotas but i think these might fix these problems if im wrong these guys will correct me...

 

loose wheel bearing is never good. just saying, scary!! haha. uh the vibration issue going away makes me want to say start there, cause small windows of mph vibration is usually an off balance tire, which essentially a bad wheel bearing can cause similar symptoms so i would start there. iacv sounds like an excellent starting point for the other issues so fully agree. not super familiar with toyo iacv was a honda guy before i was any other efi guy, but i imagine close to the same tech. if cleaning etc doesnt work, get someone to smoke your intake if you can, might have to pay a shop a couple of bucks unless you have a buddy with a smoke machine, easiest way to find vac leaks by far. if not available there is the old spray carb cleaner around suspected leaking components, intake etc while engine idles and wait for the idle to change.

 

o yeah forgot the all around rough run, tune up ever since you have owned? pull some plugs and check a burn wear chart. i think there is one on this site somewhere. id post a link but i am already late for work haha

 

Thanks a lot guys. I did just lower it so it pulls now and I need to get it aligned anyway. After that I'll go ahead and do the wheel bearing. I guess it needs to be done regardless ha!

And about the IACV, I think you guys are definitely right. I'll look up some how to's for that and get started..

I did tune it up though. Put new plugs and wires on it and changed the oil. Maybe it needs a new fuel filter? I guess I didn't do a "full" tune up so I should find those write ups too haha.

Thanks again!

 

I've had a number of wheel bearing problems on my cars and I worked in an alignment/suspension/tires shop for the last 2.5 years.
1. I've never had a tire balance issue that went away as speed increased. it's possible but highly unlikely.
2. I have had 3 separate occurrences of BEARINGS giving vibration and noise at only certain speeds, then going away.
3. Misalignment WILL NOT cause vibration. It will cause tire or suspension wear that will cause vibration. The exception is if your toe is out enough to cause the tires to hop and scrub going straight.

For the idle surging issue, set the hot idle (Ie drive 10 miles then set it) to 750 rpm and clean the IAC. for the roughness at idle, it's not the fuel filter. might be imbalanced injectors, imbalanced compression, or vacuum leaks. but as the saying goes, fix what you know is wrong, then worry about what might be left.