View Full Version : super bad misfire need help

07-26-2009, 09:48 PM
so i got done with my swap and its misfiring baddddd i cant rev the engine pass 2k rpm, at idle it sounds smooth, i put new spark plugs wires coils are all sparking, got the two icm cheked and there good tried both of them and it still missfires, can this be cause by an exhaust leak somewhere say manifold for example? do these cars have some sort of timing that can be cheked? if anyone can shime in i would appreciate it

07-27-2009, 02:51 AM
Try mass air mine did that it would miss fire so bad it sounded like it had a huge cam in it. It didn't through a code just took a guess and unpluged it and cleard it up a little so bought a new and bam ran perfect. Bad news there 200 bucks without a core. I just had a lucky guess when mine did that.

07-27-2009, 03:13 AM
Also I did a Saturn engine once and one of the injectors was not on all the way it's a simple mistake. ( the plug piece)

07-27-2009, 04:23 AM
Yeah I agree, somthing isn't plugged in right or in the wronge spot. Make sure you have the spark plug wires in the correct order. Double check the plugs too. Good luck

07-27-2009, 04:24 AM
By any chance............Did you hear this engine run before you purchased it?

07-27-2009, 09:02 AM
I would start simple and make sure the plug wires are in the right order (double and triple check this).

07-27-2009, 12:01 PM
i tripled cheked the wires and there going all in there correct spott, and no i dint hear the engine run before i bought it, coudl it really be the mass air flow sensor, when i turn on the car it sound smooth like nothing is wrong then i give a little rev and it pops like it misfiring all crazy, and about the injectors im going take a look today and chek to see if all of them are connected and all the way in.

07-27-2009, 12:19 PM
You can unhook the maf...if it runs better then that is the problem.

07-27-2009, 12:55 PM
I would also pull the valve covers and check the valves, rocker arms,etc... one messed up valve can do the same thing

07-27-2009, 09:57 PM
figured out the problem turns out that the sensor thats behind the harmonic balancer was messed up swapped it out and its good as new now all i have fix is leak on the manifolds and test the engine on a long trip and see how it behaves

07-28-2009, 08:59 AM
Good to hear, i guess you are talking about the crank position sensor. What lead you to that? Glad you got it going!

07-28-2009, 04:59 PM
i called a good friend of my dad he like our brother he told me to chek and sure enought it was that now i have to give the car a good long hard drive to see how the engine is going to hold up i got a little over 3 weeks for the warranty to expire so gotta get a move on