So I have a 2004 Tahoe flex fuel model with just starting, last night, rough idle, stumble, stall issue with no CEL, won’t rev or delayed rev. Started last night, drove, then turned off, comes during restart. Found and repaired cracked PCV connections, cleaned MAF and looked for loose connections and cracks in all engine bay/vacuum lines and fuel connectors. Used scan tool, here are the stft and ltft when it’s idling normal. I know I’m showing rich ltft, looking for ideas of what to check next.
2004 Tahoe 5.3 flex fuel intermittent hot rough idle and stall
- Thread starter Eboz
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
LTFTs show it ADDING fuel, so it's been running lean. The STFTs are okay, but the ECM has learned to add fuel before, perhaps due to the cracked PCV connections.
Throttle body clean?
How old are the O2 sensors, and are they OE, not aftermarket?
Do the fuel trims come down at 1800 or 2000 rpm?
Fuel composition -- what percentage of ethanol is in the fuel in the tank (E10?), and what does the scanner say the fuel alcohol content is? Are those values pretty close?
At hot idle, what does the MAF report in g/sec (not lb/min, please)?
Throttle body clean?
How old are the O2 sensors, and are they OE, not aftermarket?
Do the fuel trims come down at 1800 or 2000 rpm?
Fuel composition -- what percentage of ethanol is in the fuel in the tank (E10?), and what does the scanner say the fuel alcohol content is? Are those values pretty close?
At hot idle, what does the MAF report in g/sec (not lb/min, please)?
Similar threads
