GMC YUKON "Random misfire"

Hello,

I have recently had some problems with my 2001 Yukon, it a 5.3L and has 4x4. when I accelerate I get about 2000RPMs maybe and can barely get above 35mph I brought it to a local dealer for a diagnosis and was told I had a bad catalytic converter, four bad O2 sensors and bad injector connectors. I've replaced the injector connectors but its still acting up. I don't want to spend the 700-1000 on a new catalytic converter when I can just replace the sensors. Has anyone had this problem before????

You need to shop around. Seen cats for as low as $268 up to $500.

Before buying a cat check the fuel pressure regulator. I have a 2002 GMC Yukon Denali with the 6 liter engine. At 155k miles it had cold idle problems but always started fine. New plugs and wires fixed that but later it had warm start problems. I had to hold the pedal down about 1/4 and crank a long time. I found several hits about the fpr on google and that fixed my problem. Part was $50 at Autozone and simple to replace. The check for a bad one is to look for gas in the vacuum line going to it. I also smelled gas when it started. P.S. You can check for a plugged catalitic convertor with a vacuum gauge proceedure from Chiltons book or others. Good luck.

Before buying a cat check the fuel pressure regulator. I have a 2002 GMC Yukon Denali with the 6 liter engine. At 155k miles it had cold idle problems but always started fine. New plugs and wires fixed that but later it had warm start problems. I had to hold the pedal down about 1/4 and crank a long time. I found several hits about the fpr on google and that fixed my problem. Part was $50 at Autozone and simple to replace. The check for a bad one is to look for gas in the vacuum line going to it. I also smelled gas when it started. P.S. You can check for a plugged catalitic convertor with a vacuum gauge proceedure from Chiltons book or others. Good luck.

I don't think cats cause misfires. Misfires are NO spark or no fuel when there is supposed to be fuel there.

I just went thru Nightmares with My 1999 Yukon 5.7. Tried ALLthe typical repairs and nothing Worked! I had one O2 Sensor warning. I decided to replace all four! That fixed the problem!!!! Todays engines with the computers are very tempermental. Sensors feed data to CPU. CPU responds as it is programmed to. However, these responses are all in perfect World Scenario. An Error Condition in one area, creates a condition that is supposed to compensate for that, but sometimes, That Just Dont Work!!!! Why doesnt GM have Firmware or software updates like all other CPU based Hardware compnies????