darthbader001

I have a 2001 Olds Bravada. So far I have changed the Plugs, Wires, Cap, Rotor, New O2 Senser, and cleaned the EGR Valve & PVC Valve. My Bravada runs great before it gets to operating temp. Once it gets warm it starts to miss when the motor is under a heavy load. Seems to be worse when I am pulling a trailor. Anyone have any other ideas on what to check or replace? Any help would be greatly appreciated.

smacit2ya

Is the 01 The new body style? I know that the 02 actually came out in 4/01. I had an 02 with the same issue. Only thing I had you did not mention was the engine light coming on and off. Turned out to be a bad coil assembly, which on the 02 (check yours) is one per cylinder. Mine only acted up when the engine heated up and under load. A good indicator is the condition of the plugs. The culprit cylinder the plug was destroyed. Not dentonated, but carboned ruined, etc. Did you notice a plug worse than the others when you pulled them? Easiest thing is to pull the ODB codes One of the autoparts chains has a machine they let you use. Good luck, and I hope that is not your issue because the parts, and especially the labor to get to the coils is big $.

FYI, just reread your post before I sent this. You did not mention the airfilter. Sounds basic, but if you didn't check that, they clog up pretty good, and airflow under load could also be the cause. Also, the fuel filter, which should be external on the tank or frame rail, clogs up pretty good also. Acceleration and load needs more fuel pressure. When is the last time that was changed?

smacit2ya

darthbader001

Smacit2ya - plugs all looked ok when I pulled them.. One did not stand out from the others. Yes, Air Cleaner Has been replaced and Fuel filter and pump were replaced about 2 months ago.

01 has the old body style.. My nephew has a 1998 and they look identical.. His is older with more miles and mine has all the problems. Go Figure!!!

MT-2500

Always good idea to check fuel pressure.
Start with good AC Delco plugs and good wires.
Any check engine lights or a blinking light when miss firing.

Get a scanner on it and look at history miss fires.
Check for stored or history codes.
Try to pin point what cylinder or cylinders are miss firing.

Good hot blue spark to all spark plugs?

What kind of plugs and dist cap did you put in it?

__________________
Remember proper testing gives us the answer to many problems.
MT