So I called today to make an appt. This guy is my friend's coworker's husband who owns a repair shop in Napa. My friend is really particular about her cars so she said she would be taking her Nissan to this guy if she didn't have the service plan with the dealer.

My 89 4runner EFI 22re has about 400k miles on it. I don't know the exact number because the speedo cable went out last year and I was waiting to do a bunch of stuff when I take the dash off. But I digress...

When I told him the truck had about 400k on it, he immediately starts to say that those trucks with high miles tend to have head gasket problems, and that there comes a time when you want to stop putting money into it. I told him the head gasket was replaced 3 years ago and I haven't had any temp problems.

What's wrong with it now? It's got a loping/irregular idle. It's fine when it's warming up, but when I take it out after a few minutes if I'm sitting at a light it does the loping thing. I regapped the spark plugs and the rear two were too wide, so that helped with the firing and stalling, but it's still loping.

I'm thinking a timing adjustment, maybe check the vacuum system, and check the compression because if the bottom half is ok, maybe the top half is gonna need work...

Basically, I can't diagnose the problem, I want him to, but I don't need him to change the oil, change the plugs, wires etc etc. And I don't want the whole 'Maybe it's time to let her rest' stuff. ESP when he's NEVER seen the truck before.

I'm replacing the fuel filter today, I don't know how to mess with the cap and rotor but that would be something else I'd like to look at.... Guys, I just need advice on what to tell this guy and possibly if there's anything else I can do in the meantime before I take it in on Monday.

Thanks in advance.

 

If I read that right you're saying that while sitting at a light (foot on the brake pedal?) the idle will go up and down?

If the rig is idling higher than normal the it's going to pulse when you have your foot on the brake. Adjust the idle down to about 850 and it should stop.

If it's not idling high then we'll need to start looking at other things.

 

have you pulled codes from the ECM?

 

the maybe it's time to stop putting money into the car mechanic in my opinion is a guy that doesn't know what he's talking about or just doesn't want the work. Your loping idle can be caused by a few things including low coolant level, and a faulty brake booster (happens when you apply the brakes). Sure there are other things that can cause it but to be honest you're in california, there are a lot of shops over there that can give you a better opinion than maybe it's time to let her go. Start searching this forum and working on your own junk. The 22re is really an easy motor to work on for the most part.

 

At 400,000 miles, if no major engine work has ever been ( valve job , rings, rebuild ) then the first thing I would check is the compression. It doesnt matter how many tune ups you do, or how many sensors you replace, if the compression is low on one or more cylinders you have to fix that first. That is the first thing you should on any high milage engine.

As far as giving up on the truck because it has high milage, the truck will run forever if you take care of it( it may not have many of the original parts left).

The only problem with that though, is it is expensive to repair if you dont do the work yourself.

Buy yourself a manual, study it, and start doing simple trouble shooting and repair and before you know it you will be able to do everything on it.

 

Seems to be alot of these threads coming up lately dealing with the fuel cut huh?

I would like to add that if it's idling higher than normal, before changing the idle down to where it needs to be you need to look for any vacuum leaks in any of the hoses and the brake booster itself.

Checking the brake booster is easy, but has to be done carefully since you will loose your power brakes. Take the hose off the booster and plug the hose end (not the booster side). When in drive hit thhe brakes and if it does not lope then, your brake booster is bad.

Checking for vacuum leaks is tricky, but having a can of starting fluid or carb cleaner handy is a help. You would spray that around any of the hoses and their associated connections and connection between the intake manifold and head. Spray for a little bit and if the idle raises even more, then you found your vacuum leak. Just be careful spraying that stuff around things like exhaust manifolds etc etc. The stuff is highly flammable. This does not always work however.

Another good place to check for a vacuum leak is the PCV valve. Which is missed quite often. If you disconnect the PCV from it's hose and plug the hose and your idle goes down considerably, then you have an air leak in either the valve cover gasket or the oil pan gasket. If the oil pan gasket or valve cover gasket is leaking oil, there is a good chance it will also leak air which causes a vacuum leak when the PCV valve is hooked up.

 

Have the mechanic check the timing chain and check for a flat cam, also check the throttle position sensor.

 

even a 22Re with 400K is gonna be tired.
Time to Rebuild

 

i agree with OC...

dont waste money and time chasing gremlins rebuild it or have it rebuilt and itll be good for another 400K...

 

Lopes at idle once warm? If it's not the brake booster as suggested, you might try flushing the IAC (Idle Air Control) valve.

 

Thank you guys, I got some of the checks done yesterday, going to do the rest tomorrow. Will let you know if I discover something. For some reason, in my recollection of past car problems, I'm thinking it might be a vacuum problem, something about it makes it feel right.

I do want to rebuild, I just don't have a garage right now so it's not really possible right now, I'm hoping within the next 6 months though.