TravisA

Ok heres the situation..... At idle and reving it up it seems to be fine but as soon as i get on the road and put it under the slightest load it begins to sound like its missing a couple cylinders.

When it began i was sitting at a stop sign waiting for someone for a few minutes and when i pulled off its when it started doing this.

Things i've done.... Changed the plugs,by-passed the MSD box and I had also changed the oil the previous day.

Just wondering if anyones had a similar problem so i don't go in circles chasing the problem..

Thanks
Travis

shoebox

Definitely sounds ignition related. Typical to break down under a load. You might check coil/plug wires.

TravisA

I can verify if there bad by Ohming the wires correct? What is a good Ohm reading on MSD wires?

Thanks
Travis

shoebox

Ohms vary on different brands of wires. Resistance will increase with the length of the wire. Test them all. Write down and compare readings. That will tell you if one or more is bad.

Gos2Slo

Mine's done the same thing as yours twice, ran great at idle but runs like crap when in gear or a load. Both times it was because the cats were fouled/clogged. Have an exhaust shop check it out, they can fail when they get too much fuel and they melt down. I got an OR y-pipe now so I don't hafta worry about it any more, just make sure you fix whatever caused the condition before you replace the cats!!

HardcoreRM125

This is 100% EXACTLY what my car did. My ingition system checked out fine ( Shoebox IS RITE though, check the wires, coil, coil wire )

However, if you can get it on a computer, do that. Not one of those cheap scanners that are 50$ either. Mine never threw a code. Put it on my uncle's Snap-On computer, and the car wouldnt go into Closed loop, even after driving it in stop and go traffic !!!

One of my O2's was the cause of all my problems.

Bow94z

mine is similar issue. would a GM tech 1 be a good scanner to use?

TravisA

Thanks for the help everyone! My car has no cats so I guess i can rule that out..

I have software on my computer that shows all the sensor's and if i recall i was having trouble with my right 02 sensor. It was reading like .050 mV during idle? Could that be the problem?

Thanks again
Travis

HardcoreRM125

Yea thats not good. The O2's should read a near constant value in OPEN LOOP for the first minute or two, on a COLD engine. That value should be between 100-200mV

Once it warms up, and goes into Open Loop, they should CONSTANTLY flucuate in a range of roughly 100mV-900mV ...

My bad O2 was stuck at around almost 600mV and wouldnt change hardly at all ...

They are suppose to flucuate big time in that range while its idling/revving, in closed loop.

If it takes a long time for it to go into closed loop, the O2 is bad. Mine took over 7 minutes to go into Closed Loop, even after a 20 minute stop and go traffic ride to my uncles.

As for your reading of .5mV ... Are you sure you didnt mean .5 VOLTS which is 500mV ? .5mV is WAY WAY OFF.

TravisA

Ok i checked them again using freescan and they did flucuate. I had checked a few months ago and it was stuck around .050 to .100 mv. It did take a while to go into closed loop though.

I'm gonna start checking wires and see what they read.

Thanks
Travis