Its a 91 TPI with 173k mi. Engine has had virtually no problems thus far. Been on some road trips lately. Got back from a 2 hour trip last night. Car performed as usual. Get in this AM and its feels rougher, sounds rougher. Its like it shakes more. First thing I noticed were the tail pipes seeming to shake more. It also feels lacking in power on acceleration and just "doesn't want to go".

RPM's steady at 750 or so at idle. Engine temp doesn't affect the way it feels. Other guages are within normal. No missing out on RPM's when accelerating. Checked trouble codes. It only blinks the Code 12 at me repeatedly. This is despite the "check engine light" I get once a month or so at WOT on the highway, which I suspect is the EGR.

I don't exaggerate when I say this is an "overnight" change. Literally, it felt great last night and crap all day today. Thought maybe it was some bad fuel I got on the road, so I used a fuel injector cleaner and new gas.

Anyway...I'm frustrated as I'm out of town and need to figure out what the heck is going on so I can get home. HELP!!!

 

check for a burnt plug wire or two thats exactly what happend to my car this past summer... look very closely at them i found a bunch that were burnt that didnt look burnt when i quickly looked at them.

 

Has the fuel pump been replaced any time recent? Could be a warning sign of a failing pump, or several other things. Broken vacuum line or leak somewhere, EGR would sure cause this. Moisture in distributor cap or bad rotor even.

 

its a thirdgen one day it works fine, the next the radiator and power window motor blows, etc...

definitely check a plug wires and all things that are free to check out before u start buying things.

yeah my egr system is broke and has been for some time, i get code 32 when i am cruising at high speeds for awhile. but the strong still runs strong still.

 

Ok...going to check all the easy stuff first. Its probably about time for a cap and rotor.

I suspected EGR at first, but yeah, I've been getting the "highway" code for some time now without any change in performance. Funny thing is when I check my trouble codes, nothing comes up.


I'm most worried about the fuel pump. Anyway to diagnose this?

 

check the feul pressure...

 

Holy crap...I found the problem! I took a closer look at my plug wires and found one that had gotten too close to the manifold and had an inch of rubber burned off. Same wire had also been exposed lower down and was touching metal.

Time to get some looms.

Does Moroso sell single wires? I had the 8mm wires on and had to replace that burned with with a regular autozone wire.

Damn! Thanks guys. I still cant believe my car felt sooooo crappy from just one singed wire.

 

hahahaha:lala: dude i told you lol was i right or was i right... any way yeah this happend to me a couple times and i had the same exact probs so i had a good idea that was your problem too...

 

right on man.....thanks for the tip.:hail:

 

Yep...happened to me the other day as well. ONE DAY before I was heading to a Dyno session!! Had to run out and buy a generic HEI lead. After dyno run went out and bought a new set of MSD leads.

Dyno run showed a strange loss of HP at 6,200 RPM. Lost 80rwhp..then it recovered. Remembered that I burnt out my Crane PS91 coil at a race earlier in the year and replaced it with a stock GM coil that I had at the track as a spare. GM coil was still in there so I figured that was the likely culprit.

Bought an external coil ( Crane LX92 ) and removed the old GM coil-in-cap. Holy C**P!! There was a hole in the bottom of the Coil the size of a quarter!! The whole thing had blown away!! Seems when I changed the coil at the track...I was in a bit of a rush. The rubber insulator that goes under the coil had moved off center. It was actually covering the center brass button. Crane Hi-6 system just blasted right through this....carbonizing anything in it's path. Seems the coil didn't like this too much and blew itself to smithereens!!

Amazing that the car ran at all...but the only thing that turned up was this downward spike on the Dyno ( obviously a misfire ). You couldn't feel it in the car.

Car made 333HP and 360ft\lbs at the rear wheels...with a bad coil. Will go back and retest as I was expecting 350RWHP.