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Discussion Starter #1
Team,

1995 5.0 EB. I found a hole in the passenger's side header, took to a local muffler shop. They weren't able to find matching headers (brand isn't made anymore), so had gotten a new set of Basani shortys, and since it wasn't an exact match I just had them order and install both sides in case pipe diameter or shape would be significantly different.

Picked up this afternoon and the tech said "it might need a tune up with the new headers now on there, running a little bit rough." I drove off the lot and sure enough it is running very rough, actually feels like it's just running on 7 cylinders. It was 'huffing' a bit when I took it in there due to the manifold leak but certainly wasn't missing like this.

Any truth to the notion that with a new/different set of headers on I would also need a tune-up to match engine timing and flow, or did they just screw up or are trying to get a tune-up job out of the deal as well?

Thanks in advance for your guidance.
 

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84 Bronco, 351w, c6, custom doubler, np208, 5.13’s, TTB44, 9”, locked f/r
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I would guess they screwed up an O2 sensor, or left it unplugged. Or they screwed up a spark plug wire, or put the wires back in the wrong firing order
 

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Discussion Starter #4
I would guess they screwed up an O2 sensor, or left it unplugged. Or they screwed up a spark plug wire, or put the wires back in the wrong firing order
Good thought I can check both of those elements in the morning. Headers flow into Y-pipe and dual cats, so there are two O2 sensors, correct? Before the first cat and after?
 

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Definitely start with the basics. Spark plugs, wires, even distributor cap. If it was an o2 sensor I'd expect to throw a code. You should probably get a misfire code if it's the ignition.
 

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I’ve had plug wires look fine but take a total dump if you looked at them the wrong way, much less disturbed them. Agree with everything said above.
 

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Yo Justin,
Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....

See my Vacuum leak test in post #11 incl jowens126 HVAC Control Panel info & Mikey350 tests @ Help with dtc codes and idle

One way to do a quick check is to grab a vacuum gauge. Some parts stores will loan you a gauge with refundable deposit.
The vacuum gauge should read between 15 and 22 in-Hg depending upon the engine condition and the altitude at which the test is performed. SUBTRACT ONE INCH FROM THE SPECIFIED READING FOR EVERY 1,000 FEET OF ELEVATION ABOVE SEA LEVEL.
The reading should be quite steady. .
When engine is rapidly accelerated (dotted needle), needle will drop to a low (not to zero) reading. When throttle is suddenly released, the needle will snap back up to a higher than normal figure.

When vacuum leaks are indicated, search out and correct the condition.
➡Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost
.
 

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Discussion Starter #9
Yo Justin,
Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....

See my Vacuum leak test in post #11 incl jowens126 HVAC Control Panel info & Mikey350 tests @ Help with dtc codes and idle

One way to do a quick check is to grab a vacuum gauge. Some parts stores will loan you a gauge with refundable deposit.
The vacuum gauge should read between 15 and 22 in-Hg depending upon the engine condition and the altitude at which the test is performed. SUBTRACT ONE INCH FROM THE SPECIFIED READING FOR EVERY 1,000 FEET OF ELEVATION ABOVE SEA LEVEL.
The reading should be quite steady. .
When engine is rapidly accelerated (dotted needle), needle will drop to a low (not to zero) reading. When throttle is suddenly released, the needle will snap back up to a higher than normal figure.

When vacuum leaks are indicated, search out and correct the condition.
➡Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost
.
Team as a follow up this morning... The mechanic had indeed miswired the spark plug wires. Resolved. Thanks all for the assist.
 

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Glad it was something so simple..
 

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95 5.8L MAF XLT, Hedman Shorties/MF SS Y & Muff, E4OD, Man hubs, KYB Quads, 31x10.5x15, 301K miles
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Trust no one, especially "Mechanics", always expect them to try to upcharge you and as far as all my experience they usually do a $hity job cause they are nowhere near as "smart" as they think they are. You as a consumer whether you are mechanically inclined or not mechanically inclined are always at risk of being screwed over. With any problem ALWAYS start with the basics and work your way up the ladder. Good that you got it straightened out.

BTW who found the problem? You or them!
 

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Discussion Starter #12
Trust no one, especially "Mechanics", always expect them to try to upcharge you and as far as all my experience they usually do a $hity job cause they are nowhere near as "smart" as they think they are. You as a consumer whether you are mechanically inclined or not mechanically inclined are always at risk of being screwed over. With any problem ALWAYS start with the basics and work your way up the ladder. Good that you got it straightened out.

BTW who found the problem? You or them!
My girlfriend found it. :) OK, I found the 3-4 wires were cross-wired, and had her come out and confirm I wasn't crazy because I was so flabbergasted they'd done that.

Thanks again for the help.
 

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95 5.8L MAF XLT, Hedman Shorties/MF SS Y & Muff, E4OD, Man hubs, KYB Quads, 31x10.5x15, 301K miles
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Good for the "2" of yous, I'm sure it was a Bonding experience between the "3" of ya's!!!!
 

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My girlfriend found it. :) OK, I found the 3-4 wires were cross-wired, and had her come out and confirm I wasn't crazy because I was so flabbergasted they'd done that.

Thanks again for the help.
Unless she's reading the forum, too, you can take credit for that one.
 

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78 Custom - 460 - NP435 - NP205 - Sniper EFI - HyperSpark Ignition - 4.56 Gears - Front/Rear Lockers
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I'll take credit for it. You're welcome!
 

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1982 Bronco XLT Lariat, 351W, C6; 1989 Bronco XLT, 302, AOD
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I'll take credit for it. You're welcome!
You have to be careful with the plug wires. I have a brand new set of wires and was still getting a misfire. Happened to notice late one evening, when you could see the spark jumping, that one of the boots on a plug wire was layed over and letting the spark go to the exhaust manifold. Not very good wires I guess. Straightened it up and no more misfire.

TB
 
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