its an 87 iroc l98 all stock except for the new ignition that was just installed, coil wires cap rotor and plugs its firing on all 8 cylinders all the wires are plugged up and in the correct place, it idles fine but once its under a load (in gear, accerlerating it bogs down sometimes starts fo sputter and vibrate) ive checked just about everything except for timing and the egr valve. Is there anything else it could be and its not throwing any codes, its so bad it cant spin the tires on wet pavement

 

What speed/rpm and which gear does it bog?

 

i would have to say its timing. borrow a light from someone and make sure its not been altered by your mods. egr wouldn't do that... what encompassed your ignition upgrade? ignition coil, module, etc?

 

module is stock, all new msd coil cap rotor wires and bosch +4 plugs i havent altered the timing ever, from what i understand once the timing is set it adjusts its self thru the module and prom and est or something like that, but once i took it out of storage the car was lacking a whole lot of power and was missing on some cylinder(s) with the new ignition it runs smoother than ive ever seen it run but once i put it in gear or go to accelerate thers no power
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o and it starts to sputter bog down at 1000 rpm when driving at about 30-35 under normal acceleration

 

when you stored your car, did you put something in to stabilize your fuel? you might have a clog in your fuel filter.. i didn't realize you just pulled it out of storage. i had that happen to my chevelle when i had it in storage for the winter... i hadn't put anything in the gas and some stuff solidified in my filter... would idle ok but couldn't accelerate worth a damn.

 

Hey, I have a very similar, maybe same problem as you... My car will accelerate fine as long as I dont floor it, soon as I do, it wont go past 3000 while driving, but while in neutral it will tach out... I have replaced my fuel pump, fuel pressure regulator, spark plugs, had the timing checked/set, new distributor and everything in it, and I just stripped the entire top of my engine down to the heads, couldnt see a damn thing wrong... O, I also replaced my fuel filter as well, tried sever different octanes, cuz who knows anymore right? anyway, I have come to the conclusion that 1 or several injectors have gone whack... It may be a month or so until i can get to those but if your still troubled by then Ill get back to you and let you know, in the meantime if you figure out the problem please let me know wut it was.

 

leek157
Run a tank of premium gas through it.

Change your plugs to a standard type, the fancy ones do not like "storage"

 

i do run premium it runs like crap on anything else i think the previous owner advanced the timing a bit, and the fancy plugs wernt in it during storage, earlier today i was talking to the mechanic that my family takes the rest of their cars today and hes got an 89 T/A 350 TPI and he said the way i was describing it the slow loss of power until now where there is almost none and how the car was running rich due to the o2 sensor wire being broken and now that its fixed the cat converter could be all fouled up causing a very restriced exhaust, and the plugs that i took out were about twice as long as the stock length which everyone including me was supprised that the piston wasnt hitting the plugs so im thinking it might not have stock heads on it.
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and i did replace the fuel filter when i did the igintion and the old one was pretty clogged, man i was dissapointed after all the work i had done i was hoping it would be running better than i had ever seen it run but nope its worse

 

If your present plugs are too short that would explain your power loss.
I would put a magnet on the head to see if it was aluminum.
Do you still have the long plugs?

 

i put a magnet to them and theyre still cast iron, and i thought i had a few of the old plugs but i cant find them so im gona stick a pick with a 90 degree end on it and measure how long the plug hole is and compare it to the plugs

 

A plugged cat will cut power. Stand at the back and have somebody rev it up air flow should increase noticeably.

At 1000 rpm and 30 mph (OD locked up?) is a high load condition and the spark is a more likely cause.

low fuel air volume and the high load can be hard to ignite.

 

my exhaust is also making a horrible noise which i thought it was loose but when i went down there and looked at while it was running and making the noise nothing was shaking and the noise was coming from the cat, the noise is also made when the doors are shut and if you bump the muffler and the noise just gets worse and worse it used to do it in reverse only but now it does it when you start it still worst in reverse but once it warms up it doesnt make the noise so much

 

Broken pieces of cat will make noise when bouncing around inside cat and muffler.

 

yes.. and broken pieces of cat will plug a muffler in a hurry. looks like u need to be pullin your exaust apart man...