Hello to all! I am a rare poster but a daily lurker and researcher. I had a bad oil leak from my 3VZE in my '88 4Runner. I decided to do the VC gaskets and I followed the '93 3VZE section of the FSM as my guide. While removing the plenum, I tore the flex boot on the intake. I repaired it with duct tape and ordered a new one. While I was in there, I changed the plugs, wires and PCV valve. After I did the gaskets, I reassembled everything and started her up! She started pretty easily but I immediately noticed that the motor was shaking way more than normal. Obviously some kind of misfire. So, after pouring over threads here all day, here are the facts:

1. I am not sure but I think it is missing on more than one cylinder based on pulling the wires off the spark plugs one at a time.

2. I have checked all hoses and connections and everything appears to be sealed up all around. The duct tape repair, while rudimentary, is sealed up nicely and is not leaking as far as I can tell.

3. The only code currently being thrown is 42 which is because my speedo cable is broken. 42 is the speed sensor code. It is not telling me anything else.

4. The truck is driveable but is obviously down on power and vibrates quite a bit more than normal. It has a kind of throaty sounding lope if that makes any sense.

5. It idles hard at 500 and does not dip or stall.

6. Timing belt was replaced about 5 months ago and the timing marks lined up perfectly. IMHO, there are no issues with the timing unless at the distributor.

7. I have not changed the cap and rotor but most likely will tomorrow just to rule out that possibility.

8. It has been running strong for years and has never had anything like this happen before. I am not a pro mechanic but I can handle a lot. Nothing was done that should have affected it like this.

9. The fuel injectors were not touched and have never shown any signs of distress.

10. I am stumped!


Please let me know which direction you think I should be going with this. I am up for anything! I am leaning towards something simple being the issue. Thanks to anyone who has any input! I will continue to post on this thread until this problem is solved so that others can learn from it. Surely this is not the first time this has happened to someone's truck.

THANKS GUYS!!!

 

If it was running fine before you changed the gasket, I suspect you got your plug wires on in the wrong order, vacuum lines on in wrong order, a big vacuum leak, are all of your sensors connected?

 

Thanks for the reply! I have double and triple checked my spark plug wire order. It is correct. Vacuum lines appear to all be sealed nicely. I guess I'm gonna have to pull the plenum again to check everything under it. Yes. All sensors connected. Gonna run another diagnostic in a few to see if it has picked up any more codes.

 

Still throwing only code 42. I did just discover that my catalytic converter is coming apart and will need to be replaced but I don't think it is related because it has been running fine for years as it is.

 

I think I got it. Wrong plugs from the auto parts store. The gaps are all different and on at least one plug, there is no gap at all. Just another story of incompetence at the local auto parts place.

 

I get my plugs, oil filters, rotor, and cap from the dealer. About same price as part store and saves a lot of headaches and better quality.

 

That is the only way I will do it from now on. I should have pulled the plugs first. Anyway, live and learn. It is not officially fixed yet but should be by mid afternoon. Thanks!

 

After market for the most part is fine, however, depending on the age of your car, I would stick to dealer and OEM parts as Terrys87 mentioned.

Regarding your issue, on number 4:

"4. The truck is driveable but is obviously down on power and vibrates quite a bit more than normal. It has a kind of throaty sounding lope if that makes any sense."

To me that sounds like a bad fuel injector. Ive had this same issue on my 90 4runner in the past and it was a bad injector. My car felt like it had 3 cylinders and vibrated at idle and had no power.