View Full Version : EGR/misfire problems?

09-07-2006, 09:20 AM
I just threw a couple of codes on the 97 trans am and I am trying to figure it out so I am not spending a ton of money trying to fix it. I did a search here and it wasnt too much help.

First, threw a P0300 code - muti-cyl. misfire. The msd wires and coil are all new as well as the plugs. I checked them last night and I do not see any arcing or anything burnt. The engine runs perfect too so I do not get that one.

Second is P0400 code - EGR malfunction....found PVC valve hose whisling and collapsing so i changed it and put in a new valve. Could the EGR just be bad???? I have looked over all the hoses and I do not see any problems with them....its at the back of the intake so its going to a PITA to change if I have to. Anything else to look for? air pump?

Any input is appreciated.

09-08-2006, 09:39 AM
on the p0300 i had same thing happen to me started with number seven misfire, then went to multiple misfire...for me i was clogged injectors....i would change your fuel filter and seafoam it, if it does turn out to be your injectors....DONT GO BACK WITH STOCK there around 150 a peice when you can get a whole set of aftermarkets for little over 300 ...anyway this prob wont help ya any..
hey by the way you notice any diff with the msd coils and wires??????

09-08-2006, 01:23 PM
thanks for the input. I dont think the filter was ever changed by the original owner. May be worth it to just go ahead. The car runs much smoother with the wires and coil. Really no help in performance but from a tune-up standpoint, it was worth the money.


09-11-2006, 10:02 AM
I had a PO300 that a dealership said was caused by the injectors.. they wanted about $700 I think... to replace 4 injectors. I replaced em all myself in about an hour (my first time, pretty easy).

Are you sure with your new wires that you don't have one that is arc-ing? I might check that real quick first.. My #7 wire was arcing right on the block.. of course the old one was actually melted through because it's so hot between the manifolds and the block where the wire was run through..

09-11-2006, 10:58 AM
I will double check but did not see or hear anything. It is running pretty smooth so if its a misfire, its so slight that I cannot feel it but the computer can.

As far as my egr, not sure...may replace the valve on the back of the intake to see if it helps.

09-25-2007, 08:05 PM
Did you ever get your problems solved? I have the exact same problem, the exact two codes. I can tell it has a misfire but it is so slight that I didn't notice it until I got the codes. I also have a slight whistling sound coming from the engine bay.