1997 Chevy Suburban THE MISSING FIRE GUY.

Hi there,

I would hook up a fuel pressure gauge and watch the fuel pressure when it starts to falter, this will help eliminate or confirm a fuel issue.

Mark (mhpautos)

This may be related to the cold air. If MAF & MAP sensors are being affected by the very cold air, it will up set the air/fuel ratio and give driveability problems. They are expensive items to just change over to see if it works or not. I would warm up the car first and see if the air intake is using full outside air, I had a problem with a customers Toyota many years ago, cold snap caused this type of problem, I redirected warmer under bonnet air into the air cleaner and solved the problem, The cost was a small drop in economy, but that was only for a short cold spell in what is normally a warm temperate zone.

Mark (mhpautos)

To get a true picture of what is going on as far as the miss fire, is to know exactly what is happening in the ignition and exhaust. We can normally point you in the correct direction as to what may be wrong, but some times it's not that simple, especially if you are trying to diagnose something from a computer terminal. So what you will have to do is ramp up the diagnostics at bit. Codes are one thing to look at, but to see what is happening with the ignition is to have it run on an oscilloscope and exhaust gas analyzer, the scope will give you an exact picture as to what the ignition is doing, Voltages, durations, cross firings, coil problems and the gas analyzer will give an insight into the mixtures and emissions, these things you can only speculate on with out the gear. Often you can have a problem that is quite common and the fix is well known, but others are a bit more complex and some detailed diagnostics is required, I feel that you will benefit from a scope reading.

Mark (mhpautos)

Hi there,

Check fuel filter, and drain a little fuel out of old filter, is there water in it? Did you check fuel pressure with a gauge? Make sure any warm air intake is not restricting are flow, an oscilloscope reading may be required to check ignition system more carefully.

Mark (mhpautos)