Just bought a 90 305 tpi auto iroc-z convertable with 44k documented miles and while it runs, shifts, idles and drives out great it just doesn't have the grunt I remember back in the day. I owned a 85 tpi iroc from new till 88 an 55k, and it would jump rite up on a brake torque at half throttle and after launch would spin the tires over shifting to 2nd.

This 90 vert takes full throttle to slowly spin the tires on a brake torque and while the shift is snappy it not close to scratching the tires. It has no codes or misses, but has only been driven 8k in the last 10 yrs and is original down to the exhaust so my hope is its a part issue related to age.

Im looking for some advice on a jumping off point to bring some of the grunt back, Im not looking to hot-rod it or any major engine mods just some simple stuff to start.
Thanks in advance.

 

Do you have auto or manual? Auto cars came with 2.73 rear gears that would cause less grunt. Convertibles are about 100lbs heavier than coupes. Are your tires fresh? I have good tires on my 350 and it is hard to break them loose.

https://www.thirdgen.org/1990-chevy-camaro

 

Yep, new tires and a A4. Also I Looked up the stats on my 85 to compare with the link you gave and my old car had 3.23s, higher cp and 5 more hp, that plus the 1000lbs explains alot!!

Still like to squeeze a lil more out of it though. I've been looking for some advice on here about the injectors and cleaning the fuel rails and such. I'd like to just put a bigger flowmatched set in, but Im not sure if any but the stock 19lb will fit or if it will make any difference.

The folks I bought it from had it serviced before they put it up for sale and the shop replaced 3 injectors and it makes me wonder about the others.

 

What tires are you guys running? Im running newer 255/50r16 BF Goodrich Gforce sports and when the tires are cool in the morning and the motor is also cold, I can roast the tires, but within 10 minutes, the tires are nice heatsoaked and sticky from the 170* asphault that even a squeal from a stop doesn't happen.

Sticky new tires in the summer and 2.73s aren't helping you in the comparison. 100lbs won't make much of a difference. That's like having your gf in the car with you, unless she's a large marge.

But lets say it is the injectors, have you checked your spark plugs for wet fuel? Is the car hard to start in the morning? Do you have Volt meter? Those things can help determine if the injectors are bad.

Another thing to think about is how long was the car sitting with the same gas in the tank. I bought a 91 T/A and it had been sitting for months. The gas had gone bad and performance sucked. So get rid of that gas fast if that is the case.

Good luck.

 

It's time for some seafoam and new plugs/wires. When I got my 350tpi it would hardly even chirp the tires and I have 3.42's. Did a tune up and ran some seafoam through the top and end my 'problem' went away.

 

it has new Falken 245/50/16 rubber. I mis-read tho thought he said verts were 1000lb heavier, 100lb makes more since. Starts right up in the mornin, Dont have a meter, yet.

Guess I'll start by cleaning the fuel system, dumpin the old gas and a tune up

 

Chances are if everything checks out fine, I would chalk it up to summer performance with new tires and 2.73s.