any ideas?

[lcasados]

I just bought a 1991 3000GT VR4 a couple of weeks ago, and I love it. I have been dreaming of getting one of these beautiful cars for about nine years. Finally, I got it. Now I seem to have some problems. I'm not sure why, but I don't have any power. I am in the process of replacing the spark plugs and spark plug wires; hoping that will give me more power. At least a little more anyway. I have a feeling that thats not the only thing wrong with it. The RPMs don't want to go past 4.5k in any gear, and I can't accelerate worth a crap. Also, if anyone knows of a way to get a hold of a 1991 3000gt service manual, would you kindly let me know. Thanks.
lee

[Wilson_Shaw]

Sounds like at least one of your Catalytic Converters is bad.

[YogsVR4]

I don't see how his cats would be doing this based on the fact it was the plugs that were changed.

It may be as simple as a bad plug. Or you replaced the plug wires in the wrong order.

Changing the plugs will have little bearing on the amount of HP you'll produce. Get an open air filter, boost controller (and a decent gauge for it) and an open exhaust. You'll be flying then.

[chris26969]

my friends GSX had one bad plug , he couldng get past 50mph , odd but hey he changed it and it workd. Try that .

[Prelewd]

Check the plug gaps also... always.

[Wilson_Shaw]

The reason that it might be the catalytic converter(s) is because he is not able to go beyond 4.5k rpm's. A bad catalytic converter would not allow as much exhaust to pass through as a good one. Since more exhaust is trying to get out at higher rpm's than at lower rpm's, the engine will have a tougher time making any power when its rotating that fast. Also, because it has no where to go, the exhaust gets backed up into the engine. This could cause some serious engine damage if left unattended to.

Checking the spark plugs and the spark plug wires is also a good idea, but that doesn't sound like the problem, or at least all of it. Even with a bad spark plug or two, you should be able reach redline in first gear. Where bad spark plugs really hurt is in low-end power.

[chris26969]

i see you own a SC2 , i dont follows those too often , how much HP do they run? Fast?

[Wilson_Shaw]

It has 124 h.p. at 4,800 r.p.m.s and 122 ft. lbs. of torque. I read in either Road & Track or Motor Trend that it is able to hit 60 mph from zero in 8.5 seconds at sea level, and has an electronically limited top speed of 124 mph. Although its not that fast, it is fun to drive and gets decent gas mileage (30 m.p.g.).

[chris26969]

not bad.

[ttamn92]

first check your cats
sec. check your boost controler make sure you are making at least 9 lbs of boost my 92 had no pwr i put a good boost guage on it and found i was only making 6lbs (wastgate press.) do not trust stock boost guage! good luck

[Trogdor]

do u know how that sc2 compares to a stock honda civic ??? also do u know if they are the same engine as like the 2000 ???

[Prelewd]

Originally posted by Trogdor
do u know how that sc2 compares to a stock honda civic ??? also do u know if they are the same engine as like the 2000 ???

How about you make a new thread for this in the saturn or civic forum instead of stealing this guys thread.

[FlamePaintn]

Check timing and timing belt...if it jumped due to wear, intake valves and exhaust valves will not open and close at proper times, reducing power. Although not 100%, carbon on your plugs may indicate a timing issue. Just had similar problem with my celica 'vert...low power, revved only to 4000 (instead of 6000). Acted as though it was a fuel restriction or breaking down coil...but timing belt had jumped significantly. Good luck.

[Im2Fast4U]

How many miles does it have? Has it had it's 60K service? If you aren't sure, just do it to be safe. Like FlamePaintn said, it could be the timing belt so 60K is a must. Like others said, it might be the plugs too.

I highly doubt it has anything to do with the pre-cats or cat. Your theory on them holding back exhaust gas is um........well I just don't get it. Are you suggesting they may be clogged with something? If there is anything jamming them that means it came from the engine and then he has bigger problems than his cats and normally the only thing that goes wrong with the cats is a bad O2 sensor which I guess could have an affect too, so you might want to check those out. Other than that, I really don't know man. Good luck fixing it and congrats on the buy (even if right now it isn't working out for you too well).