yellow351mustang

Was wondering if anyone can help me. I am new to late model Mustangs, have owned classics for years. After having to sell my '69 Fastback with a 351 Windsor a while back for financial reasons (yes this killed me!!), I have been able to acquire a really nice '88 GT from a dear friend (Back in the saddle again). The car is in (rare) fantastic shape with low mileage and a mostly stock Speed Density 5.0L except for a 2.5" MAC Cat-back that sounds GREAT! My question to you all is, I'm happy with the cars performance and drive ability except for a hesitation or a feeling of the engine falling flat above 3000 RPM. It doesn't matter if I accelerate from standing stop or if I'm on the highway and want to down shift and pass. It feels flat above 3000. The exhaust sounds sweet and makes wonderful noise, but just doesn't feel like it is pulling as hard as I expected a HO 5.0 to pull. Maybe I'm still to used to the 351, but really doesn't feel like it pulls any harder than the 4.0L OHV in my Explorer. I don't have much money, so big expensive engine mods are out (for now), including the MAF conversion. The person that owned the car before me did all of the usual freebie mods: remove silencer, adjusted TPS, K&N filter (Well not free) and of course the Cat-back (stock 4 CAT H-pipe). Below 3000 it feels great, good and strong. So I don't know if there is something simple I can do or am just stuck with the way it is. I did check the plugs back over the summer and they look normal. It passed our state emissions test with amazing flying colors. The guy even said this car runs cleaner then other cars that he sees that are 10 years newer. The one thing I know can make a huge difference is the rear gear, it has the stock 2.73. But actually, I'm quite happy with the 1900 RPM's at 70MPH on the highway in fifth rear. With Gas in the high $2/gal. this gear will stay in for a while. Maybe I'm just out of luck, but was wondering if anyone had any ideas. Again, no budget so big engine work is out for now. I know, my hands are tide. Other wise I love this car, it is a rip to drive. Thanks for anyones help. Sorry for sounding ignorant.

turbosha

thats a stock stang for ya ! being a density car and 273's , thats as good as it gets.thatswhy everybody on this site is looking for power. stock sucks

89 fox

heads and gears are the 2 most felt mods...the gears would definately be cheaper

tmajikman

+1 on the gears, I was lucky with my 87, sd as well. but it had 3.73 gears already in it. not the fastest, but she pulls really hard, I had a 98 explorer w/ the V8 and the explorer could not pull anywhere near as hard as the stang. If you can do them yourself, you could save yourself some decent money.

dimebag

no thats not normal... sry... i disagree w. the 1st post... i have an 88 gt, speed density... it seems like it doesnt start to pull untill 3k.. from 3k-52/300 it pulls like all hell... and its stock... only differance is i have stock 3.08s, but yours should still pull hard at 3k, not fall on its face

samseed101

Well whaddya expect? You went from a badass 351 to a stock 302, lol.

dimebag

hah, good point... still dont think it should fall at 3k... they make power starting at 3k

nitrous_bob

i will say you might have an issue to fix

hard to tell, but actually the 5.0 should run better than the 351 imo

i had a bonestock '88 notch 5-speed, 2.73's and street tires and i got it to go 14.20's

i would start w/ the following, recheck the tps voltage, do you know how ?

you need a digital miltimeter, and 2 safety pins.

i would regap all the plugs at about .045"

this is to check if spark is weak, if you close them up and the power picks up, spark is weak from something

i would check the timing (the most probable culprit)

if you run 87 , run about 12* btdc , if you use 93, run about 14*

check fuel pressure, you'll need a guage, and some line, if you wanna check it under load, but simply hook into the schrader valve on the fuel rail on the rt side of the engine

if the cap and rotor are feirly new, fine, if old, replace them

unless the fuel filter was swapped out in the last 30k or so, do that too
(if you do it after you tied into the fuel rail, and b4 you started the car back up....you will have a zero pressure fuel system, and save some gas spilled down your neck and arms)

otherwise kill the pressure off, by unplugging the inertia switch in the trunk or hatch, then fire the car up, let it stall, turn it over a bit more (5 more seconds maybe)

thats about it really, if your still in the sam boat , you just need gears

mileage does not suffer like you might think, i run my 5-speed w/ 4.10's, daily driver, 50 miles rt to work, another 20 miles rt on tues/thurs going to school

i get 21 mpg, i tach about 3000 doing 80 mph, even w/ the ac blowing

93 LX FiveO

some things to keep in mind

the car is stock, and its nearly 20 years old.
fox bodies have terrible gearing


that stock h-pipe and headers are really holdin u back too. i upgraded to bbk shorties and h-pipe and the difference was night and day. you can feel the difference in the pedal, which is where it counts

will

Poss converters not flowing/restricted.