Backfire and rough running efi 302 needing help

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Sep 18, 2014 | 11:38 PM

JamesF-250

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Backfire and rough running efi 302 needing help

My 86 ford f250 has the efi 302 and is running rough when in gear and backfires a little. Any ideas why? And could it be something besides timing? Ive retimed it, fuel pressure check, checked the sparkplugs, replaced the fuel pressure regulator and fuel filters and spark plugs wires and coil are just a month old

Sep 18, 2014 | 11:40 PM

JamesF-250

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Rough in gear i meaning puahing the throttle when its in drive

Sep 19, 2014 | 07:27 AM

ctubutis

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From: Denver Metro Area, CO

First thing to do when diagnosing a computer-controlled engine is ask the computer what it thinks is going on; here's how:

Ford Fuel Injection » How To Run a Self-Test

Sep 19, 2014 | 10:01 AM

reflector

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f-250 87 - burnt valve on #1

Have you done a compression check?

I've been having similar issues with my '87 f250 302. It runs fine until the engine warms up, then it has an awful misfire, causing it to run really rough under any kind of a load (as soon as it's in gear and you give it gas). I finally gave up chasing possible culprits: egr components, tps, aic, vacuum leak, etc. I broke down and took it to a real mechanic who did a compression check and found #1 down around 120, with the rest in the 180's. Further inspection revealed the burnt valve on cylinder #1.

Hope this helps.
-j