TylerM

I've had my 93 4wd pickup with the 3vze for a little over 4 years now and I've had nothing but headaches fixing all the neglected issues from the previous owners. The most recent is a shuddering issue that literally happened overnight. I was having an issue with my battery not charging consistantly. It would start fantastic and five minutes down the road almost not start and then five minutes farther down would start like new. I replaced the negative and positive battery cables alternator/voltage regulator and 80amp fuse and replaced a rigged job of wiring to the fuse block in the engine compartment with the correct size wire. Didn't fix it. I found my grounding strap on the rear of the engine was burnt. I replaced it and problem solved.
Next day the fan clutch died on me. Replaced it drove it home working fantastic. The very next day I have a horrible shuddering issue. The engine acts like it's timing is off or air/fuel mixture is bad or it's misfiring. Under further inspection I noticed that my battery had shifted and hit the power steering pump and ate it which threw battery acid everywhere. Also the distributor cap was arching out. I replaced the rotor and cap. I messed with the timing as much as the distributor would allow and it gets worse either way I adjust it so I don't think my timing belt jumped a tooth. I also cleaned the cold start injector. All of the relays and fuses in the blocks check out fine. I've taken out the throttle body and used my volt meter and my TPS sensor is in spec. I replaced my wires/plugs about 3 years ago. That's my next attempt. Any other thoughts would be greatly appreciated.

TylerM

Found the problem. Somehow my number 3 spark plug wire came disconnected from the metal piece that attatches to the plug. Fixed that and now it runs better than ever since I've gone through just about the entire air/fuel system.

rworegon

Glad you found it and it was something easy to fix.

tacomanut

My 3.4l 2002 (200k miles) Tacoma's timing belt went out on the highway between Idaho and Utah. I got the belt replaced but ever since then the engine shudders right at 4k RPM. It only happens every once in a while (when I shoot a gap on the freeway) so I've let it go a while.

Right when I get to 4k I can feel the whole motor shake and lose power. I have to back off the gas or it keeps shuddering. The guy at O'Reilly says that no codes come up relative to this and that if it were the cam position sensor there would be a code.

Some background. This is a really beat up truck (so I'm selling it soon) that I regret buying even though I love tacomas and it's my second one. I've had all sorts of issues with emissions, I've had to replace sensors etc. because the previous owner didn't change the oil. (It burns oil so I'm assuming that's what happened.

I recently didn't pass emissions and they said one of my cats was destroyed. I think it was the first one. I think they replaced the second one, as I can see the shiny metal halfway down my truck. Maybe it's the broken-up cat that's blocking exhaust and causing the shudder?

I did have the engine light come on but it was P0301, misfire on cylinder 1. I recently had a tune up but they didn't replace the spark plug cables/wires so I'm going to buy wires and see if that fixes the misfire issue. I think it's unrelated to the 4k RPM shudder.Well I read about exhaust backpressure online. So being the mcgyver I am I thought "how could I relieve pressure?". I pulled the upper oxygen sensor and put it in a plastic bag with a lighter taped open so the bag would fill with butane and the sensor wouldn't pick up to much oxygen. I revved the motor and.... same issue! I guess it's not backpressure....
I really could use your help as I'm trying to sell the truck. Thanks so much!