99 SR5: Significant missing & backfire through intake

[DriftPunch]

My '99 has developed a problem where it badly misses and backfires though the intake when cold (and the environment is cold). It clears up slowly as the engine warms up, and disappears by the time heat can be produced by the heater core.

Once warm, it's fine. It's all but undriveable when in the throws of missing.

Has anyone experienced this? What was it? I've got no CEL as it seems to cure itself by the time it's warm enough to log a code.

 

[techno]

If you do manage to get an error code it will probably be P0300, 301, 302, 303 or 304.
I would check all the wiring conections first, make sure they all look fine and are securely connected. Check all vacuum hoses too.
Next check the spark plugs. Make sure they are clean and the gap is correct. If you can, check to see if each plug is actually producing a spark when the engine is cranking.
Those are the easy things to check first, after that you are getting into ECM voltages, injector checks and fuel pressure stuff.
Have you tried using an injector cleaning additive in the fuel yet, something like seafoam? That may help.

 

[imagemaker]

Did you figure out the issue? I suffer the same issue with my 2000