Is it just slow?

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dhunterd08

New Member

Jun 3, 2011

9

0

1

Dec 22, 2011

#1

• Dec 22, 2011

• #1

Alright, I have a 99 mustang GT. When I first bought this car, I was really excited about the potential of it. The body was next to perfect, and it seemed to have been taken care of. It does have 133k miles and is an auto which I am sure contributes to the problem, but I just feel like the car is so slow and runs terribly(especially below 2000 rpms). I also feel like it pings a little when going up hills especially. It has had a new rear end, new plugs, trans flush, coolant flush, new SLP catted X pipe, and a CAI. I have thought about trying seafoam. It does get me from A to B, and I dont want to expose any problems. My question comes down to should I just give up and deal with it since it has so many miles or keep trying to make this thing what I think should be "right"?

 

txredgt

10 Year Member

Oct 26, 2009

1,343

33

69

Dec 22, 2011

#2

• Dec 22, 2011

• #2

Gear and tuner pronto.

 

twogts4us

15 Year Member

Apr 1, 2004

4,188

12

79

Dunedin, FL

Dec 23, 2011

#3

• Dec 23, 2011

• #3

Yeah lower gears (higher numerically) will help. The mod motors just don't make a lot of power down low.
As for running rough, I'd really stay away from Seafoam for just the reason you mentioned - exposing a bigger issue.
As for pinging while going uphill...are you running 91 or 93 octane gas?

 

D

Deleted member 38176

Dec 23, 2011

#4

• Dec 23, 2011

• #4

I'd have a compression/leakdown test done

 

slayerripkdc

15 Year Member

Jun 3, 2003

1,341

16

59

brewster ny

Dec 23, 2011

#5

• Dec 23, 2011

• #5

like Nightfire suggested. Compression and leak down test. If everything is in good running order 4.10's and a tuner! Is it very hot where you live? I know when it is hot and humid my car feels so much slower but in winter time it runs like a raped ape!

 

bradfier

Member

Mar 2, 2010

142

0

16

Dec 23, 2011

#6

• Dec 23, 2011

• #6

If your oil pressure is normal, there shouldn’t be anything wrong internally. I would start using a higher grade fuel. I have had good results with Sunoco. If your after a better launch I would go with 4.10 gears and a quality dyno tune from a performance shop. Other than that it is 12 yr old motor, I'm sure it has lots of life left but if you want to play you gotta pay ... so to speak

 

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tomv84

New Member

Sep 14, 2010

4

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1

Dec 23, 2011

#7

• Dec 23, 2011

• #7

These motors run great and last a long time - I bet you just need to continue with the tune-up stuff to get it back to its full strength. You've done plugs, great start. I would suggest going through it more thoroughly - MAF cleaning (get the CRC MAF cleaner spray), new fuel filter for sure at those miles (unless its been changed), maybe some quality injector cleaner (chevron techron or redline) instead of the more drastic seafoam. New front O2 sensors would be a good idea (little more money here). I'm sure I'm forgetting something also. Assuming you have decent compression, these additional tune up steps will probably get you running right. Definitely don't get a tuner until you're running right stock.

 

Stumbaugh

Member

May 13, 2010

903

13

19

Russellville, Ar

Dec 23, 2011

#8

• Dec 23, 2011

• #8

My car never felt fast to me, but did to other people. It felt strong on spray, but not on motor. Take it to the race track and see what MPH it runs, that will tell you if it's down on power.

 

blkstanger

Member

Sep 18, 2011

45

0

6

El Cajon Ca.

Dec 23, 2011

#9

• Dec 23, 2011

• #9

I would sea foam it. Could just be carboned up real bad. It's not going to hurt anything. Pinging is a huge clue to carbon build up. How did the plugs look when you changed them?

 

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dhunterd08

New Member

Jun 3, 2011

9

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1

Dec 25, 2011

#10

• Dec 25, 2011

• #10

Thank you for the advice everyone. I think I will just keep troubleshooting the issues. I am going to try some better gas, MAF cleaning, and some chevron injector cleaner first. I may still seafoam it, but I just dont want to put any more money into this thing in the case it exposes more problems. After that I will check the compression and see where I am at. I may consider some gears and a tuner if I can get it running a little bit better, because sometimes I do feel the motor has a lot of power. It just does not seem to translate into speed. I really think there is some underlying issue. I find it hard to believe there would be such a following of these vehicles if this is how they performed in stock form(even automatic).

 

D

Deleted member 38176

Dec 25, 2011

#11

• Dec 25, 2011

• #11

bradfier said:

If your oil pressure is normal, there shouldn’t be anything wrong internally

Click to expand...

Wow, that couldn't be any more wrong.

 

trinity_gt

10 Year Member

Jan 31, 2003

3,125

81

99

Canada

Dec 25, 2011

#12

• Dec 25, 2011

• #12

dhunterd08 said:

I may consider some gears and a tuner if I can get it running a little bit better, because sometimes I do feel the motor has a lot of power. It just does not seem to translate into speed. I really think there is some underlying issue. I find it hard to believe there would be such a following of these vehicles if this is how they performed in stock form(even automatic).

Click to expand...

Keep in mind that these cars had 260 HP at the crankshaft when stock and new. That's less than most family sedans nowadays (Honda Accord, 271HP; Hyundai Sonata I4T, 274HP; Toyota Camry V6 268HP etc etc...) and many of those cars will keep pace with a stock or near-stock automatic New Edge GT. I'm not sure how you're assessing what constitutes "slow" or if you're down on power. Is it just subjective (e.g. the car just doesn't "feel" fast?) or do you have quarter mile ETs and MPHs and/or dyno numbers?

You say the car "runs terribly(especially below 2000 rpms)": Can you be more specific? What issues are you seeing? Bucking? Misfiring? Is the MIL (aka the "check engine lamp") on? Are there any codes stored in the PCM?

Do you know why the car required a new rear end? Did you do that service or did the previous owner? Was the car abused in its previous life and if so consider that anything that will hurt an 8.8" axle may also hurt a stock automatic transmission which may lead to slipping in gear, for example.

I think we need more specifics of the symptoms to help identify what, if any, issues there are.

 

slayerripkdc

15 Year Member

Jun 3, 2003

1,341

16

59

brewster ny

Dec 25, 2011

#13

• Dec 25, 2011

• #13

If your car is in good running order it is possible that you are just use to the stock power. Cars that have less then 300 hp feel slow to me because I am so use to it now but when ever I give my friends a ride in my 2v they all say how hard the car pulls. Probably because they are all use to Hondas lol. HP is a drug and even 400, 500, 600hp feels slow to those that get addicted! Bring it to the track and check the mph. A 5spd car should be around 97 mph bone stock. Im not sure about an automatic.

 

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unirok

Member

Oct 6, 2011

37

0

6

Dec 27, 2011

#14

• Dec 27, 2011

• #14

Seems like it might be somewhat in your mind. I have a 2003 CVPI and a 2003 Mustang GT and i swear the crown vic feels quicker picking up speed. Both of them feel veryslow to me and its a seat of the pants feeling. I drove a 2004 maxima the otherday and it feel works quicker. These days you have to choose your opponent as the stop light wisely lol. That boring looking camry in the next lane may just lay waste to you. my GT has a flowmaster exhaust and I tend to be more gentle on the throttle because of the loudness.