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Discussion Starter #1 (Edited)
I am pretty sure it is a fuel issue. :mad:
I usually run 87. Last few tanks put in 93.
Timing is not advanced but maybe a few degrees up.
I recently replaced a few things. put in +2 plugs, cap, rotor, wires, coil. I replaced the fuel filter last weekend. I am replacing the pump this wkd. What size should I use?
When driving hitting the gas it hesitates, pops etc. sometimes. When driving or full throttle it has no go like it is running on a couple cylinders.
It revs up fine but if I hold it down it only revs up to around 4500 and sounds like it is running on a few cylinders.
It happens more when it is cold. A few times riding down the highway and hitting a dip or a bump it pops up front, like a backfire in the cylinder.
I am going to put a gauge on it this weekend and see what it reads.
What psi should it be reading when off, on and driving??
I want to install a gauge on it at the same time. I was thinking a 2 5/8" 0-100 psi gauge outside in front of the windshield.
Any pictures, thoughts, comments, concerns, advice would be greatly appreciated!
 

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what the **** is a +2 plug? whats your timing at?
 

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Discussion Starter #3
bosch plugs +2's
idk exactly what the timing is at. Had this guy check it and he said that it was at nothing but maybe a few degrees advanced.
 

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you should ask your friend to be more specific with his info, for all we know hes doing it wrong...did he pull the spout connector before he checked the timing ?
 

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Discussion Starter #5
not sure didn't ask.
 

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Discussion Starter #6
what fuel pump should I get and how big?
I have stock injectors and mass air.
more info on the car:
CAI, 75mm throttle body, cobra upper and lower, pulleys, factory a/c, no smog, elec fan.
All upgraded from clutch to gears. spec stage 2, flywheel, fork, etc. all that.
A5 rated for 550hp, drive shaft, 3.55's

I plan on doing heads cam intake in the future. with a procharger in the far future.
 

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I always say 255lph, that way it gives you room to grow and you only drop the tank one time. any extra fuel that your engine doesnt use will be sent back to the tank.

just my opinion
 

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Discussion Starter #8
thank you
 

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MY car won't rev pass 4,500 rpms either! If i were you i would check your timing.
 

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Discussion Starter #11 (Edited)
Yea I just found this. I am going to check it out right now.

http://www.moddedmustangs.com/ford-firing-orders.html

Another thing is, If I cut the key off then back on real quick, it runs fine. But just for a moment then it's back to hesitating and popping.

Update. Over the weekend I changed the fuel pump. Installed a 255.
 

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Have you put a gauge on it yet? it should read 39psi at idle with the vac line off the regulator. Sounds like your pump is bad to me.
 

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Discussion Starter #13
Installed a 255 pump and an external gauge. The gauge reads 38-39 at idle and around 41 when I rev it up or get on it.
I am checking and adjusting the timing tomorrow. I should put it at 12 or 14?
Out of the few firing order pics I found, the one that works for now was the 1.3.7.2.6.5.4.8
The one that comes up that does not work at all is the 1.5.4.2.6.3.7.8
 

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id put your timming at stock until you figure out the issue
 

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Remove the Bosch plugs and replace with copper core Motorcraft or Autolites. Bosch makes weird driveability issues. At dealer when there was a problem and the Bosch were in they went out.
 

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Discussion Starter #16
The timing was way advanced. Maybe like 20 or more. I set it at around 11-12.
I replaced the plugs with autolites.
re-checked the firing order. Made sure everything was tightened up. and.....
it is still doing it! :mad:
WTF else could it be???
Maybe the distributor?

Is that the right firing order?

I have been thru a few tanks of gas.
 

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You're on the correct firing order. That's the H.O firing order or the 351w order. The other is the non-HO firing order.

Next thing I would do is put a vac gauge on it and see what you come up with. Have you checked for vac leaks or blown intake gaskets?

 

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Discussion Starter #18 (Edited)

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Ok... I'm having a similar problem with my 93 5.0 check the fuel pressure its prefect vacuum line on or off! The tps (throttle position sensor) is good!! I changed the fuel filter.. well my dad had a F-250 with a 460 with a head job, cam, and pistons pushing 400+ HP I own the truck now runs great he told me never to adjust the Distributer with a timing light it was like 36° advanced.. I put the timing light on my Mustang adjusted the timing to 10° it ran light total crap!!! Let my dad adjustedit runs alot better just still can't runt full throttle after he left I check the timing it was 30° advanced.... Next just for shits and giggles I unplugged my MAF sensor and drove it... it launched the hardest it ever has since I've owned it plug it in runs like crap ANYONE HAVE THOUGHTS ON THAT?
 
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