Still Slow

[Mindcrime]

2004 GT, 29,000 original miles. Completely stock. Changed fuel filter, changed injectors, changed oil, changed plugs, changed coils, new brakes, new IAT sensor, and still slow as hell. Next up is a Fidanza clutch, tune, and 3.73 gears. If that does not help I am parting it out and buying a 2009 GT/CS.

 

[98COBRA281]

2004 GT, 29,000 original miles. Completely stock. Changed fuel filter, changed injectors, changed oil, changed plugs, changed coils, new brakes, new IAT sensor, and still slow as hell. Next up is a Fidanza clutch, tune, and 3.73 gears. If that does not help I am parting it out and buying a 2009 GT/CS.

well fuel filter, injectors, oil, plugs, coils, brakes and IAT add zero HP, so i dont understand why you say "still slow after that" and a fidanza clutch wont add any power or make it any faster either. throw a set of 410's in it, with an o/r mid pipe, what ever muffler's you like, maybe some under drive pulleys and a throttle body plenium combo, with a tune and that should wake it up a decent amount...


and why buy an 09 gt/cs? nothing but a 3v with a graphic on the sides... buy a 11' 5.0 instead....

 

[Mindcrime]

It was not an attempt to make the car faster per se, it was an attempt to figure out why the car was not nearly as fast or quick as it should be in stock form... it has no codes coming up to give an indication as to why it won't accelerate as it should. I thought poor performance levels (in regards to acceleration only) would come down to a select few things. 1. bad plug(s), 2. bad coil(s), 3. calipers hanging up, 4. Intake air temperature sensor going bad, 5. clutch slippage, 6. clogged or dirty fuel filter, etc.
I am not sure if the rear axle and gears are original or out of another car, like a v6 mustang (if that would bolt up), or some other gt. If these gears are not the stock gears I have no idea what they are yet. Have to check on it. The clutch is only going to transfer the available power, if it's even the clutch to start with. If it is slipping under WOT then a clutch will give me more power than I have now, cause this thing will not get out of it's own way. I can't really explain it. I checked the things people told me to check. I can't afford to have it analyzed by 10 different people and have the issue persist. I have had it checked by two mechanic shops, and still have no idea what is holding the car back. Those two visits cost me over $1200. It does seem to run marginally faster when cold, but once it gets to normal operating temperature it seems to get slower. I did change the thermostat thinking it might be sticking, although the temp gauge never went past halfway. Even then the car seems like it runs hotter than it should. It is the only way I have to work so I am getting to the point where getting rid of it and getting something else would be easier than messing around with this car.
And trust me, if I could afford the 2011 or 12 5.0 I would get one. Right now it is about $8000 more than I can afford.

 

[N8Dogg98]

How does it feel above 3500 RPM's? It should feel somewhat sluggish below 3500 because these OHC engines don't provide a whole lot of low end torque compared to other V-8 RWD cars.

Do you have anything to compare it to? Anyone you know have a similar car you can do a quick race up to the speedlimit on the highway to see if it's all in your head?

 

[Deleted member 38176]

Have a compression/leakdown test done.

 

[Mindcrime]

For the record, this issue came up right after I bought the car. I posted about it and got some real good feedback. I had someone who was gonna check it out for me, and give me a decent price for the effort, but it fell through. So I tried to do the best I could with what I had. I took advice and tried to do some of the things suggested. It is frustrating to finally have a mustang again only to have issues and no clear definition of what is causing the problem.

 

[Mindcrime]

Nightfire, how much does this test cost? On average? Does it involve me not having my car for a day?

 

[N8Dogg98]

What other types of cars have you driven recently? If you've owned/driven a LS1 Corvette, Camaro, or GTO, then yea your car probably feels slow. If you've driven a Dodge Caravan and question whether or not it is as fast as the van, then you may have an issue.

 

[Stumbaugh]

If you have had the car for a while and get on it regularly, it's going to start feeling slow because you are getting used to the power. My car does not feel fast even on the spray to me. But if I take someone for a ride in it that has not rode in very many fast cars and spray it, they think it's insane.

 

[Mindcrime]

N8Dogg,
Honestly, it seems like the engine is fine, and it revs smoothly and quickly. If you rev it to around 5 grand and drop the clutch it will squeal the tires but then once it hooks up it sounds like you are hauling ass, but it doesn't go anywhere. The odd thing to me is that if the clutch was slipping it would rev and you would feel the car lose momentum as the rpms climb. It doesn't do that though. The rpms do not fluctuate, it does not seem to lose momentum, but rather I tend to have very little actual acceleration with the rpm's staying steady, and climbing smoothly as I gain speed. Also once I get to 5th gear at say 5000 rpm's, as soon as I let off the clutch in 5th it bogs down and falls on its face. Trying to accelerate in 5th gear is like driving a frickin 86 escort!

 

[Mindcrime]

What other types of cars have you driven recently? If you've owned/driven a LS1 Corvette, Camaro, or GTO, then yea your car probably feels slow. If you've driven a Dodge Caravan and question whether or not it is as fast as the van, then you may have an issue.

I have a 2006 f-450 flatbed 6.0 powerstroke w/160,000 miles, and my wife has a 2004 f-150 fx4 5.4 triton w/ 88,000. And yes sir, I got outrun by a gti golf badly, a 6 cylinder camaro, and recently had the misfortune of trying to catch up with a little old lady in a damn Toyota Corolla! It's not my driving I assure you! Embarrassing none the less.

 

[Mindcrime]

If you have had the car for a while and get on it regularly, it's going to start feeling slow because you are getting used to the power. My car does not feel fast even on the spray to me. But if I take someone for a ride in it that has not rode in very many fast cars and spray it, they think it's insane.

It honestly never seemed fast. I mean it goes a little, but overall it is a dog in my opinion. If it turns out there is nothing is wrong with this car and it is just my imagination , then Ford should be ashamed of themselves for putting a mustang badge on these cars. I had a 1990 lx coupe and it would eat this car alive with just the exhaust and intake I first put on it, from stock. I could jump that car sideways in 3rd gear with the tires smoking. This car cant get sideways unless you turn it and rev it to 6 grand from a rolling 20!

 

[N8Dogg98]

If she revs up fine in neutral, then I'd suspect something else is causing the car not to accellerate at the rate you should expect.

What happens if you're on the highway at 60 mph and you put the car in neutral?

If it seems to slow down quickly, I'd suspect a brake problem. These cars are notorious for sticking caliper pins on the rear brakes. It also could be a problem with the e-brake.

I don't think a wheel bearing or damaged bearings in the differential would cause a problem, but who knows.

 

[98COBRA281]

This car cant get sideways unless you turn it and rev it to 6 grand from a rolling 20!

sound like it just has a dog a$$ stock 3:27 gear in it, throw 410's or 430's in it and i guarantee you next post will be different...

we put my old set of 430's in my friends 95% stock 99 gt, car will spin a decent amount of 3rd on the 2-3 shift not power shifting at 60+mph..

 

[trinity_gt]

This is way too subjective. You need either a dyno run or two to show rwHP and/or you need to take it to a track and get a 1/4-mile time for it. A bone stock PI GT making 260HP at the crank is not really a fast car; many grocery-getters, family sedans and SUVs are making much more HP and are faster nowadays. Maybe your car is performing exactly as it should.

And a 1990 LX? Slower than a stock PI GT and I highly doubt they were capable of sideways-in-third-gear-smoking-the-tires type performance given that back in the day they ran 15-second quarter mile times stock, a full second behind the PI GT.

 

[1fun281]

Sounds like your just expecting it to be faster then it is, gotta learn how to drive it, these cars power bands are alot different then other sports cars, 3500+ should pull decent, dont tell me you have your ac on when doing pulls a/c makes my car feel like its towing a boat! Put some 4.10's or 4.30's in it and i gauruntee you will change your mind about this car quick, the stock gears really kill these cars potential

 

[Deleted member 38176]

Nightfire, how much does this test cost? On average? Does it involve me not having my car for a day?

I've never had one done so Im not familiar with the specifics. I'd imagine that it would take an hour or two. Call your local Ford dealer.

 

[89lxsport50]

My 225hp 89 LX with 273s feels faster from a stop than my 260hp 02 GT with 373s and a 93 octane race tune. The reason is the torque band is down low on the 5.0s. The 2v 4.6 is an absolute dog down low. They don't really start pulling until you rev them to about 3500 - 4000 rpm.

 

[jrp1588]

Odd, my brother used to have a 95 cobra about 5 years ago. After driving my GT, he said it felt a lot quicker and more responsive.

 

[Mindcrime]

If she revs up fine in neutral, then I'd suspect something else is causing the car not to accellerate at the rate you should expect.

What happens if you're on the highway at 60 mph and you put the car in neutral?

If it seems to slow down quickly, I'd suspect a brake problem. These cars are notorious for sticking caliper pins on the rear brakes. It also could be a problem with the e-brake.

I don't think a wheel bearing or damaged bearings in the differential would cause a problem, but who knows.

It coasts and seems to slow down fine. Does not slow down overly quick or to a point I would suspect anything hanging up. But I just had brakes put on it and they did not indicate a problem with calipers hanging up. Does not mean it aint happening though. I am sure they could miss that if they were not thorough. I considered bearings, but without having any odd noises coming from that area of the car I dismissed that as a possibility.