TNRabbit

Could be a bad spot in the TPS, could be distributor-related...

ThePlumber

Update. I have discovered that a mechanic at some point removed the rubber tube from the throttle body and tore it on the bottom side. There was a tape repair there that failed. So basically there was a hole at the throttle body after the meter vane.

I shaped it up and taped it up. Took it for a test drive from cold to operating temperature. Stopped, set a minute. Started it up and drove back.

It runs MUCH better currently. Not perfect, but I can be picky.

I have no idea why the codes have been stored in the ECU. But I'm thinking the behavior it was exhibiting was because it was getting it's fuel/air mixture all fouled up at a couple of points.

Sound crazy? I'm NOT a mechanic. But I am a pretty detailed plumber.

ThePlumber.

BoostinChick

I have pulled my throttle body off a couple times, trying to think what hose ran underneath it? Only one I can think that goes underneath is the one to the TVV.

If any hose was off, it was a vacuum leak. This causes a rich/lean condition because un-metered air is escaping the system.

TNRabbit

Check ALL vacuum lines with an UNLIT (!) propane/MAPP gas torch with the engine idling. If it idles up, you have a vacuum leak at that point! I found an "unfindable" hole this way on mine underneath the large vacuum hose to the A/C VSV on the passenger side fender well. Works like a charm.

ThePlumber

Thanks everyone. The truck is running MUCH better now. The tube that had the hole/tear is the larger one (about 3") that has the PCV valve connection on it and and connects to the throttle body.

It was torn and split two different ways.

Priced it today-$60.00+. Pretty steep for the material you get. But hey, I AM cheap.

So, I "repaired" this leak and the truck is running pretty good. And within about 5 miles of the test.......

THE CHECK ENGINE LIGHT CAME ON AGAIN. Duhhhhh......

Guess it's back to the EGR from hell. Thanks for the Propane/MAPP trick. I always have both around. That's a fantastic tip as there are so many places for things to leak and difficult to find them.

Thanks again. Running better but I hope to stick around. Many things to do....

EGR......Exhaust...... etc..... NEXT!!!

ThePlumber.

TNRabbit

I had an issue with my EGR control valve:

ThePlumber

Can you identify the "Control Valve" for me? Or is that another name for something?

I've cleaned the passageways of and replaced the EGR, Vacuum Modulator, Coolant Temperature Sensor, and have tested the EGR VSV as the manual states. The EGR Temperature Sensor is connected. I have not tested it yet though. Next on my list.

The VSV works everytime instantly when charged.

Gonna' do your torch test soon.

I think one think that happens often is damage to the vacuum modulator. I replaced mine in the CEL chase. I cracked the old one open to inspect it. Many may know but I didn't-internally is just a paper thin rubber seal. It had a small tear in it.

I replaced it, the CEL when out on its own within about 5 miles. But like a ghost....she has returned.

Thanks for reading and all information.

EDIT: Duhhhh.....I just figured out your pic is a vid. New to the forum. You were talking about the EGR. Gotcha'.

ThePlumber.

BoostinChick

I am lost here, anyone have a picture? I always thought the large PCV tube went from the PCV to the intake mani?

ThePlumber

You may not be lost at all. I may be the one that's lost. Here's a pic of the tube I'm talking about. I'll use the terms as I understand them-anyone more knowledgeable feel free to correct.

This tube (about 3" in diameter) connects at what I call the entrance to the throttle body. The other end connects to a "collection box" that's black plastic. Then out of the collection box to the airflow sensor/air cleaner. Working backwards in flow from the throttle body to the air cleaner.

Then the small tube connected into the larger one is the PCV valve. Right? Wrong?

Finally, you can see my botched up "repair" of the original "repair". There was a hole underneath on the large tube that could not be seen without removal. Sucking air and causing erratic driveability.

ThePlumber.

BoostinChick

The PCV is located on the passenger side underneath the intake plenum, pretty much underneath all those vacuum hoses and what not on the passenger side valve cover.

The tube you have in the picture goes from the intake accordion tube to the valve cover. That black plastic thing is more like an elbow than a PCV.

ThePlumber

Thanks Chick. I azz-u-me-d it was the PCV valve based on ones I'd seen & replaced before.

No wonder I couldn't get it to rattle some.

Wanna' argue about water heaters?

ThePlumber.

Nuckleblood

I also have a slight misfire when opening the throttle at idle to about 2000rpm. I just replaced the head gaskets, removed the EGR and pair reed valve and cleaned the intake and throttle body and every other part and adjusted the valves. I put new pintle caps on the injectors, and let carb cleaner sit in the injector and blew it out with air. It didnt have much of a misfire before disassembly. A vacuum gauge is at about 15 inches right under proper green vacuum. I am waiting for a can of 3M fuel injection cleaner to come to directly inject cleaner into the fuel rail and also check fuel pressure. all new tune up parts. I have a screw below the idle adjustment screw I cant find out what it does. it is not the dashpot screw but a screw sticking out of the throttle body. Anybody know what that screw is for? it is a California truck so maybe it is a screw most dont have. It actually ran better before disassembly. I am at about 10 degrees BTC timing. I'm going to check for vacuum leaks with a propane torch but have close to normal intake vacuum. What a bunch of vacuum hoses gone and also removed the hard lines under the intake. it has 160,000 miles and I could still see honing marks on the cylinders. Mainly dont know what the second screw does, and then injector cleaning is my next steps. Anybody have that second screw on a 93 3VSE? I also need to check the throttle position switch to make sure carb cleaner didnt get in it. My first post, but a lot of experts on this site.