Gonna need some new injectors...eventually

Heep's started misfiring off-idle and just off-cruise throttle. You know - I'm rolling along at cruise and put a little pressure on the throttle and it stumbles instead of smoothly increasing RPM. I can still get around by mashing the pedal, but I'm going to need to do something soon. For the moment I just added some fuel system cleaner, but I don't expect that to fix it in the long run.

I think this is related to my earlier thread about missing in similar situations.

Get some Ford pulls - they'll work fine (302 OEMR are 19#/hr, as I recall.)

On a related note - have you checked your TPS? I had a wicked miss and stumble off-idle, and a brutal flat spot from 2200-2800rpm - a new TPS gave it a seeing-to!

5-90

Yeah, I hadn't gotten around to looking up the Ford injector IDs yet.

I was planning on new injectors, TPS and IAC when I get a 62mm TB, but I might have to settle for a new TPS, cleaning my stock TB and pulling some Ford injectors.

I had a thought earlier today. This thing does still have a distributor. It could be cross-firing.

With a ball game and cubscouts tonight, a ball game tomorrow night, and a ball game Thursday night, I just hope it doesn't crap out before Saturday.

XJ Dreamin' said:

Heep's started misfiring off-idle and just off-cruise throttle. You know - I'm rolling along at cruise and put a little pressure on the throttle and it stumbles instead of smoothly increasing RPM. I can still get around by mashing the pedal, but I'm going to need to do something soon. For the moment I just added some fuel system cleaner, but I don't expect that to fix it in the long run.

Click to expand...

Those symptoms do fit in with the TPS being the problem.

Dr. Dyno said:

Those symptoms do fit in with the TPS being the problem.

Click to expand...

Yeah, I know. I hadn't been able to come up with a condition to match the symptom until this morning. I was thinking crossfire, but that would be worst at high manifold pressure when you're cramming the most air into the cylinder. This is more like misfiring while the RPM is changing. It occured to me this morning that that sounds like a bad distributer bearing. It's fine when there is no torque load on the distributor shaft, but when you try to change RPM by opening the throttle the distributor shaft rattles around in the loose bearing (bushing really). I've seen it plenty of times in old Mopar stuff. I'll see if I can find a few minutes soon to check side play in the distributor shaft.

Thanks for your comments, guys. I appreciate it. This diagnostic process would go quicker if we were sitting around talking over a few beers. This bbs diagnosis is annoyingly dry.

edit: sorry 'bout that. HIGH manifold pressure - not low :dunce:

Ran smoother today. Maybe the fuel system cleaner is actually doing something.

It's back, today. Seems to be intermittent. Dr. Dyno: Probably, 5-90's description is more accurate. TPS cured his. I'm starting to lean that way with this one.