slight misfires

[89Bronco58]

89 bronco, EFI 306 , when i first start driving in the morning the truck misses a bit here and there, almost like in 3 second intervals, once its good and warmed up, the misfires get smaller and softer, and evevtually there is none at all, the plugs and wires are good, the cap and rotor are MSD and were replaced a few weeks ago to try and help this problem, but did nothing, i have replaced the coil, all the fuel injection is working properly, the thing runs perfect except for every 20 seconds or so i get a misfire or two....coolant temp sensor?

 

[bidibronco]

Cracked or miss-gapped spark plugs?

 

[89Bronco58]

no the motor is still new, less than 10k on it and the plugs were put in then and have been fine since the motor was first started, and id think that might be it, but its only once in a while and stops eventually once i have drove for a half hour or so, so im not thinking thats it

 

[Seabronc]

Have you checked the timing? As your engine warms up, it changes.

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[89Bronco58]

timings on perfect

 

[firelt90bronco]

I just fix a problem like this on mine. I replaced the ECT and it helped alittle, but I turned the distributor counter clockwise to lean it out alittle and its definately better.

 

[Seabronc]

timings on perfect

How did you check the timing, with or without the SPOUT connector hooked up? It sure sounds like the timing may be a little too advanced.

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[89Bronco58]

it was set with it disconnected, the timing has been the same for a long long time, this problem just started outta nowhere, i know it isnt the timing