92 GT power problem...

[Benboi92GT]

Was wondering if anyone has any ideas because I don't know much of anything besides the very basics of the 302, or any engine for that matter. I always don't quite know how to describe the problem but I'm going to try my best.

6 months ago I bought a 92 GT with unknown miles down in Florida (I live in Missouri) for 2 grand. According to the guy it sat in his backyard under a tree for 8 months before I bought it, because he never got around to building it. He drove it 5 hours towards me in Florida, where I met him and then proceeded to drive it 15 hours back to Missouri. Car ran like a dream. Turns out the gas tank had rusted out and by the time I got it back all the rust had pretty much blown through the entire fuel system and I had to replace everything from the fuel tank to the injectors. Since then I have put on a gt40 upper/lower, bbk fender-well cai, new tps, new iac, 24 lb injectors with matching maf housing, all new required gaskets, ac delete/smog delete, 3:73 gears in the rear. I have been through the surging idle checklist and have the timing, tps, etc. all set correctly. Guy I bought from said he "thinks" it "may" have a mild cam in it. I don't know because I havent been any deeper than the intake.

Now the problem is that the car still feels just... slow. Sure, I can smoke the tires allllll day in first but other than that it really doesnt impress. However, the problem is sometimes going into second and a lot of times going into 3rd. If I am getting on it, say I shift into 2nd at 35 hundo / 4 grand rpms, I will come off the clutch and give it gas and as the rpms start to go up in second gear the engine sound will change, it will get higher like its struggling and then drop a couple hundred rpms and then scale up again as normal, does it worse in 3rd gear. I really wish I had a better way to describe whats going on but I don't. An equivalent scenario might be that as you are blowing up a balloon and as you are blowing it up some air escapes and it deflates a bit before you blow it up the rest of the way... lol

Anyway, Im just trying to trouble shoot the problem. Could it be a bad water pump, bad compression, bad head gaskets, bad axles? I really dont know and I dont know enough to not throw parts at it. Sorry for the ty vague description of whats going on. Hopefully someone understands wtf I'm trying to get across, haha.

Thanks guys!

 

[91TwighlightGT]

Any check engine light or codes? Maybe a clogged catalytic converter or a restriction in the exhaust?

 

[Benboi92GT]

Any check engine light or codes? Maybe a clogged catalytic converter or a restriction in the exhaust?

No cats at all. Also just installed new o2 sensors

 

[Benboi92GT]

Also, no CEL. Could a clutch/tranny problem be causing my symptoms?

 

[MaRu_GT]

What Distributor you have ? you need also to check all of your plugs are igniting.
I had something similar to hesitating rpm when I accelerate. when I did the right plugs for that head, changed the distributor to motorcraft with TFI module, I got my car running great.
Also check for any vacuum leaks especially from intake.

 

[Benboi92GT]

What Distributor you have ? you need also to check all of your plugs are igniting.
I had something similar to hesitating rpm when I accelerate. when I did the right plugs for that head, changed the distributor to motorcraft with TFI module, I got my car running great.
Also check for any vacuum leaks especially from intake.

MSD dizzy but have the stock tfi module on it, with the MSD tfi module it was hesitating at 2 grand, stock one it works perfect no cut outs

 

[Boydster]

I had a problem with an MSD Pro Billet dizzy... had an intermittant miss I couldn't get rid of. Replaced TFI, PiP, cap, rotor, wires, lots of stuff. Problem never went away until I installed a stock dizzy. Something with the body of the MSD or the rotating windows in the top were causing all my probs...

 

[Benboi92GT]

Yep, didnt have a miss after I installed stock tfi on MSD dizzy. This just started.

 

[91TwighlightGT]

Very strange problem. It would be great if you could run it on a dyno and have some data to look at.

The fact that there is a noice associated makes me think of a restriction in the intake or exhaust. I can't imagine that this is a tranny or clutch problem, it just doesn't add up. I wonder if you don't have an accessory locking up, like an A/C Compressor, or perhaps you are losing voltage from a weak alternator. You would think that they would be noisy, though.

Are there any other symptoms? The car idles fine? What happens when you floor it in 5th gear?

 

[Benboi92GT]

Very strange problem. It would be great if you could run it on a dyno and have some data to look at.

The fact that there is a noice associated makes me think of a restriction in the intake or exhaust. I can't imagine that this is a tranny or clutch problem, it just doesn't add up. I wonder if you don't have an accessory locking up, like an A/C Compressor, or perhaps you are losing voltage from a weak alternator. You would think that they would be noisy, though.

Are there any other symptoms? The car idles fine? What happens when you floor it in 5th gear?

New alternator, a/c delete. When I floor it in fifth rpms shoot up, no power to the ground, then they drop a couple hundred until basically I get to a speed where the rpms can increase normally, if i accelerate slowly then its fine, its when I stomp on it the power just isnt there

 

[jrichker]

Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

 

[91TwighlightGT]

New alternator, a/c delete. When I floor it in fifth rpms shoot up, no power to the ground, then they drop a couple hundred until basically I get to a speed where the rpms can increase normally, if i accelerate slowly then its fine, its when I stomp on it the power just isnt there

Hmmm... that sounds like a worn clutch to me.

 

[Benboi92GT]

Thats pretty much been the consensus on the other boards I'm on too

 

[Boydster]

Sounds like a good ol' slippin clutch.