2003 4Runner rough cold start

[influx99]

03 4Runner SR5, v8, 40k miles.
Last evening I started the truck after it was sitting in the driveway for about 6 hours. The engine vibrated pretty noticeably for about 3 seconds, then was fine. This morning, cold start, same thing, although the vibration was a little more noticeable, but still for about 3 seconds. Drove it about 20 minutes, parked for 5 minutes, restarted, no vibration. It's definitely a cold start thing. Weather tempurates are in the 70s/80s.

I would describe the vibration as being very rough and then winding up to no vibration at all. I wonder if it's a rough cylinder? Something electrical?

Any ideas what's causing the rough start? $-wise, what are we talking worst and best-case scenarios? Of course the warranty just ran out 2 months ago...

Update: The rough cold start has not happened again in the last 2 days...

[Art808]

I recently had a similar problem with my 2003 4Runner (V6) SR5. Upon cold start in 80 degree weather, a loud repetitive noise occurred. It sounded as if the fan was hitting up against something. I immediately turned the engine off and tried again. This time it was a little slow cranking, but started, and with the same noise. But I also noticed an odor as if something was burning. I immediately turned the engine off again and waited until the next day. The next day, the engine would slowly (very slowly) crank, but would not start. That's when I called a tow truck and towed it to Toyota's service department. Toyota didn't get to it until 2 days later; however, they told me that upon starting the engine, everything sounded and checked out normal. Sure enough, when I picked up the vehicle, it did not display any symptoms. I call this the mystery starting problem.

Did you solve your problem yet?

[Brian R.]

I'm betting that it's a moisture/ignition thing. I wouldn't worry about it unless it gets more and more frequent.