Hey guys I am new here, so I am diesel mechanic and recently got a 1992 bronco with 5.0 for free, so my problem are rough idle sorta when you rev it seems to tapper off but still there feels like a misfire. Did change plugs and wires and two injectors, has a msd cap plugs are gap to .045, so not sure more bad injectors, burnt valves, pip sensor, strange thing happened when I got it running it died a few time and that was it, I cycled the ignition and could not here the fuel pump so maybe pip sensor?

 

Suggestions ?

 

Suggest you pull codes. Then someone who is more knowledgeable than me will get back to you.

 

I would definitely pull codes first to try and help narrow down the issue.

If you have no codes, or fix the underlying issues any codes bring up, then I would probably next check the fuel pressure to rule out low fuel pressure causing the issue.

If the fuel pressure checks out good, (even if fuel pressure doesn't check out good), I'd check the timing. Make sure it's set properly and if so, then I would start checking the ignition system.

You said plugs and wires are changed, make sure the wires aren't arcing against your exhaust or each other. If these are okay, I would consider looking into your ignition control module and pickup coil. I've had lots of issues with pickup coils in the past...

 

Brand new accel plugs routed as the ford manual said on line what is the fuel pressure supposed to be I chech quick and it was between 30 and 35 psi during running. But I will chech timing and the ignition module and the pick up ( looks original ) just has a msd cap on a stock distributor.

 

I believe the pressure is in specs. Someone correct me if I'm wrong but I think its supposed to be around 32psi when running so yours seems good.


As for the ignition module, if yours is mounted on the distributor and it looks original, it's possible it could be the cause of your issues. They tend to get heat soaked (distributor mounted modules) and cause issues. However, they more commonly cause no start/stalling issues rather than misfiring. The pickup coil is a sensor inside the distributor around the shaft. You pretty much want to replace the whole distributor if the pickup coil is bad, because you have to take the distributor out and disassemble the shaft to get the new pickup coil on.

Now if you haven't replaced you ignition coil, it wouldn't be a bad idea to replace that for a tune-ups sake if it appears original, but I believe there is a way to test them also. I don't know the procedure though.


I'd definitely pull codes before you start replacing any parts though.
Check KOEO (key on engine off) and KOER (key on engine running) for codes using a paperclip. There should be a writeup on these forums on the exact procedure. It's pretty easy and free to do, plus should help pinpoint any issues.