Engine 1993 5.0 LX w/ 15k Miles.....no power above 3000rpms

Sheriff01

Member
Apr 13, 2020
16
7
13
48
FL
just got this beautiful black 93 5.0 5 speed with 15k original miles.....the car inside and out is pristine as is the underneath and engine bay. The exhaust and engine are 100% stock and factory original other than a K&N air filter.

Although I do have some gremlins.....here Are my issues.

1. very hard to start...takes 2-4 attempts...once it catches it idles well with no issues.
2. under normal driving it’s drives decent, few small stumbles at most but regardless if slowly accelerating or hard on the throttle, the car hits a wall at 3000rpms and falls flat and won’t go above 3500 rpms. It has zero real power and has the feel of something with a governor on it.
3. exhaust is stock and 28 years old... wonder if the the cats/ muffler may be clogging as it doesn’t have the old rumble I remember from back in the day.
4. no engine check light.

What I looked at so far

1. the air filter was clean as was the throttle body....I need to check to make sure it’s opening fully.
2. got new super unleaded gas in and I added some injector cleaner just to see what it would do

While I’m going to do some mods in the near future, I’d like to ensure it runs well before moving on. Although the mods may find my culprit.

My plan for this car is ——


1. Cobra Intake /Manifold
2. BKK 65mm TB
3. BKK CAI
4. BKK MAF
5. FRRP 19 lbs Injectors
6. 130 Amp Alt
7. Ford Racing 3.55 gears
8. GT 40 Heads w/ 1.7 RR
10. Dual Exhaust with Flowmasters ....maybe just 2 hi-flow cats if any.


any suggestions on what may be causing my current issues with no power or acceleration ?

Thanks
S01
 
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Monkeybutt2000

Active Member
Aug 11, 2019
292
209
53
48
Lafayette,IN
Few suggestions,mostly on your mod list. First,you sure you wanna do it? That's a low mile car,and they're starting to bring some good money in original condition. If I were you, I'd do the gears first and see if you're satisfied. If you do decide to do the mods,skip the BBK stuff. Besides their headers (which are really good) most of their stuff is crap. As far as your power loss,have you diagnosed anything?
 

Sheriff01

Member
Apr 13, 2020
16
7
13
48
FL
Thanks for the info on BK stuff.

Just ran codes with a reader.......

Key Off - 11
Key On - 12 ( Idle RPMs Out Of Range / High)

Ran both test twice to verify.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,116
9,253
224
Massachusetts
Had similar symptoms with my car. Chased it for a while thinking it was fuel. Replaced the pump and fuel pressure regulator and didn’t fix it.

Ended up being a junk aftermarket coil. Stuck a low-mileage used unit in (I trust it more than aftermarket junk) and problem solved

Car showed no codes at all
 
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TomSlick2

New Member
Apr 28, 2013
2
0
1
68
Waukegan,ILL
just got this beautiful black 93 5.0 5 speed with 15k original miles.....the car inside and out is pristine as is the underneath and engine bay. The exhaust and engine are 100% stock and factory original other than a K&N air filter.

Although I do have some gremlins.....here Are my issues.

1. very hard to start...takes 2-4 attempts...once it catches it idles well with no issues.
2. under normal driving it’s drives decent, few small stumbles at most but regardless if slowly accelerating or hard on the throttle, the car hits a wall at 3000rpms and falls flat and won’t go above 3500 rpms. It has zero real power and has the feel of something with a governor on it.
3. exhaust is stock and 28 years old... wonder if the the cats/ muffler may be clogging as it doesn’t have the old rumble I remember from back in the day.
4. no engine check light.

What I looked at so far

1. the air filter was clean as was the throttle body....I need to check to make sure it’s opening fully.
2. got new super unleaded gas in and I added some injector cleaner just to see what it would do

While I’m going to do some mods in the near future, I’d like to ensure it runs well before moving on. Although the mods may find my culprit.

My plan for this car is ——


1. Cobra Intake /Manifold
2. BKK 65mm TB
3. BKK CAI
4. BKK MAF
5. FRRP 19 lbs Injectors
6. 130 Amp Alt
7. Ford Racing 3.55 gears
8. GT 40 Heads w/ 1.7 RR
10. Dual Exhaust with Flowmasters ....maybe just 2 hi-flow cats if any.


any suggestions on what may be causing my current issues with no power or acceleration ?

Thanks
S01
Hi. I bought a 96 cobra 5 speed the guy I bought it from put all new plugs wires everything take it on the road hit 4000 rpm falls flat on its face. Took it to Bobs garage in Waukegan . He found gas tank rusty and feul pump only putting out only 60 percent . New pump and gas tank runs real strong. So check feul pump might work. TomSlick2
 

TomSlick2

New Member
Apr 28, 2013
2
0
1
68
Waukegan,ILL
Had same problem with my 96 cobra .All new plugs ,wires ect. Had the feul pump tested only putting out 60 percent. Had to replace pump and gas tank ,runsreal strong now
 

Sheriff01

Member
Apr 13, 2020
16
7
13
48
FL
So.... been tinkering today.

tested fuel pressure

Key On - 0
Running -21
Removing Vac Line - 21 no change
Thumb over hole - 21 no change
When I turn car off... pressure drops steady to 10 then falls to zero quick

I changed the fuel filter ..... same numbers. Gas that came out was clean

I bit the bullet and changed to Fuel Pressure Regulator..... what bitch!!!! Same exact numbers !!!!!!!!! I definitely have a fuel pressure problem somewhere.

all that’s left is the pump in the tank ????

I tested the the tester on my truck and it read it correctly so the pressure tester is working properly.
 

Sheriff01

Member
Apr 13, 2020
16
7
13
48
FL
Busy day!!!! It was indeed a split line in the pump.

1. replaced fuel pump/ mount and new sending unit

2. BBK mid H Pipe with Hi-Flow Cats

3.BBK Ceramic Headers

4. Flowmaster American Thunder CatBack with polishes tips

Car sounds amazing and runs like a champ. I of course kept all the original parts and hardware. Thanks for all the help and advice. Think I’ve decided to keep the car pretty much stock except for 3.73 gears and exhaust as it’s so nice and original.
 
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