Engine cutting out at low RPMs

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May 27, 2004 | 09:21 AM

sactrack

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Joined: Sep 2003

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From: Roseville

Engine cutting out at low RPMs

I'm driving a 90 Bronco w/the 302EFI and AOD tranny. The problem only occurs in D and OD and only in the 2400 and lower RPM range. When under a load and under 2400 the truck shudders and feels like the engine is missing. 1st and 2nd gears don't do this at all, and D and OD only at the mentioned RPMs. I had this problem before (last October) and after changing plugs it disappeared, but that didn't fix it this time. So far I have, changed
- plugs (used good MotorCraft ones)
- wires (MSD 8.8mm.. changed then last Oct. when this occured last time)
- distributor cap & rotor (both MSD)
- fuel filter
- PCV valve
- had the tranny flushed last Oct cause thought it might have been the torque converter
- changed TBI module on the distributor for a MSD one last Oct.

I'm starting to run out of ideas. When I had the truck at the tranny shop last time they told me it was definitely not the tranny but that it was an engine problem. The engine is pretty well stock... i have an Edelbrock dual 61mm bore throttlebody on it, K&N filter system, but stock other than that. (has 150k miles on it) Any ideas? this is really starting to **** me off

May 27, 2004 | 09:47 AM

buckeyebronco

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Joined: May 2003

Posts: 575

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From: Orlando, FL

Same thing happened to me when I let a fried who is a chevy guy work on my beloved ford. My problem was solved when I went through and routed all of the plug wires so that none of them crossed unless absolutly neccisary, and make sure the 7 and 8 wires are at least 3/4 inch apart at all times and that the coil wire is arched up and over all of the other wires. I have the same truck and I found that I just had to take the time to make sure that I wasn't getting any electrical interfierence in any of my wires. How this helps.

May 27, 2004 | 09:51 AM

sactrack

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Joined: Sep 2003

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From: Roseville

yeah, I probably could be a little more careful about my routing. I'd heard that this could cause a problem... but didn't think it could cause a problem of this magnitude. I'll re-route when i get home this afternoon and see what happens. thanks

May 27, 2004 | 10:36 AM

Kemicalburns

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Joined: Jul 2002

Posts: 14,285

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From: Bend,OR

whats with such a large throttle body on a stock motor, do you have exhauts upgrade and headers?

run your wires good, might check your coil voltage or just get a new one. have the engine codes pulled that might give you some ideas to. have you replaced the o2 sensor??

May 27, 2004 | 10:39 AM

sactrack

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Joined: Sep 2003

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From: Roseville

sorry... i forgot to mention a few other mods.... yeah.... have a pair of shorty headers, dual Flowmaster exhaust w/3" pipes. Also replaced the coil w/a MSD TFI coil last October as well when this went down the 1st time around. The TB, exhaust & headers have been on for a while though w/no problems so I'm positive that's not it.

May 27, 2004 | 12:20 PM

fcarruth

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Joined: Oct 2002

Posts: 573

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From: Medina, Tn.

I agree with the routing of the plug wires, especially 7 & 8 I think(Driver Side). Also, I was having similar problems that you described and I replaced my distributor and no longer have the problem. I also went from less than 13 MPG to almost 16 MPG with a stock AutoZone distributor.

Good luck,