Okay, i thought I had fixed my problem but obviously i havent. Heres the story:

Most of the time when cruising, occasionaly when accelerating, the car would suddenly shake violently, with the tach bouncing around, and sometimes pop from the exhaust. (It would also stall out at times too). Figured it was the exhaust valves sticking open (popping from exhaust) so last week my dad and i went and relashed the exhaust valves. Everything seemed to be working great, car didnt shake at all, nor stall.
Now the problem:
Driving home tonight the damn thing started shaking crazily again (again w/ the tach bouncing around). I really didnt notice a popping from the exhaust, but the thing stalled out like 5 times before i got home. One other interesting thing i also noticed, when i was driving down the street, i had the pedal to the floor but the car just slowly crept along and barely accelerated (didnt even redline before i reached the end of the street!) . Finally got the thing home after stalling another couple times and just said f*** it.

I was thinking that it could possibly be electrical seeing as i have a slightly burned plug wire on cylinder 3. However, if it were arcing i would think the other cylinders would function as normal, thus accelerating the car as normal, not barely chugging along. I had checked the plugs, cap and rotor when i lashed the valves last week and they all seemed fine. No carbon or moisture inside the cap. I also replaced the fuel filter two weeks ago so I know that it's not clogged up. I figured the cat couldnt be clogged or else this would be happening all the time, which it isnt.

My only thought is something else w/ fuel delivery. I am guessing the fuel pump is dying?? Its the only reason i can think of to explain why the car wasn't taking off when i had the pedal on the floor. I dont know of anything else that could be screwing up in the fuel system... injectors are new w/ the engine (approx 2000 miles).

If anybody else has any ideas please let me know. I really need to get this fixed fast, mainly for my own safety... not fun at all when turning, car stalls so you have no power steering, making you almost hit the car sitting at the light :\

Sorry for the length, and thanks for any help.

 

Do you have a cat?

 

yupp.... but if it were clogged wouldnt this be happening all the time (if not more often)?? The car seemed to run fine for a week until tonite. I had even driven it for almost an hour straight a few days ago and all was fine. Im just so aggravated at this damn car right now....

I will try and pull the clamps off and see if i see anything - or just take the cat off entirely and see if it happens again.

 

You're right, I missed the part about it being from time to time. If it's clogged the cat should glow, or the car will run warmer than normal.

 

Hey fellow michigan resident! Yeah, I am gonna take a stab at this and say its your fuel pump on its last legs. On Oct. 22, just after filling up with gas, my Iroc-Z started shaking violently when going down the street. Awful feeling isn't it? It only started 1 time after that... had to tow it home. I will be droppint the tank in the next week or so and changing the pump before I bolt up the new exhaust. If ya need someone who has changed a fuel pump before, email me in a week. heh...

 

I'd say you might have a problem with the fuel pump also. I had the same thing in 2 cars. In an 85 fiero, it would shake and after shutting it off and restarting I could drive for about 5 minutes. Then it would do it again. In my Z after the car would warm up it would do it also. In both cases after replacing the pump the problem stopped and never occured again.

Has your pump been making any more noise than normal? That would be a good sign. Also hook up a ful pressure gauge and test it when it's running and when it starts having it's problem. Most likely what you are experiencing is a drop in pressure and it's starting to starve the system.

Good luck and keep us informed!

 

check your fuel pressure with a guage. If it is not the pump and you have pressure, it would be a big job to drop the tank for nothing.

My car did something silmilar to that, but it had a new ac delco fuel pump. When I checked the pressure, it was leaking off.

when I pulled the tank it was the 3 inch rubber fuel line in the tank that had a crack in it. The car was loosing fuel pressure.

I had replaced a few things on my car, thinking it was something else. I spent 300 bucks on the car and it ended up being 3 dollars to fix it. a piece of hose and two new clamps.

 

i'll check the fuel pressure and see if anything is screwy.

The strange thing is that this has never happened in idle - only when the engine is under load cruising down the street.

I also havent noticed any weird noises, but then again that could be because of the damn exhaust I-pipe vibrating against part of the frame

I'll keep ya guys informed if i figure out what the hell is wrong w/ it.... and thanks again

 

sounds sort of like what mine did when the fuel pump took a ****..it would start everytime no problem but the tach would go nutz and the car would try to die...id have to sit there and rev the hell out of it and try to go...if i made it down the street without stalling 3 or 4 times it would start running fine and idle good and everything until turned off then it would mess up again shaking and acting very pissed off...then for awhile right as school started it stopped and the car ran fine for a month then one day the car overheated (had nothing to do with the pump failure) and after that it barely ran...to the floor i was going 10mph all the way home got it home and that was the end of it didnt even start after that. so i had someone crank the car while i had the fuel lines disconnected and not even a drop came off...so with no real mechanical experience i ripped the rear almost out and put ina new pump..took 2 days but after that she ran perfect...pisses me off that anytime one thing breaks something stupid will happen first like the overheating...i thought for sure i warped a head or cracked the block...

 

BAK,

You should check pump pressure, but may also want to remove a fuel line and test pump flow as well. Into an open container, you should be able to flow at least 1 pint in 15 seconds. If not, you may have a filter clogging, line restriction, pickup screen clogging, or a failing pump.

Good luck. Keep us posted, since it might not even be fuel related, but this will eliminate those possibilities.