Bogs down

[Scott Martin]

Too little information to diagnose over the internet. But always have to check the basics when it happens: spark, fuel and air. Compression is likely not a possibility. You have to "catch it on the act," you know what I mean?

It may be losing fuel or something about spark advancing/retarding, but could also be some vacuum leak that happens intermittently? A scan tool with Live Data is a MUST on these type of problems! Fuel trims is what I would check. Ideally should be < 15%+\- on the long term. If both banks are lean or rich, then likely a fuel delivery problem.

Also check all other sensors and their output values obviously, such as MAF, TPS, MAP, O2s, etc. Good luck.

I do know someone who has the necessary equipment to do all that.

 

[Curt]

I do know someone who has the necessary equipment to do all that.

I see you know Spicoli's dad too...

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[Scott Martin]

Too little information to diagnose over the internet. But always have to check the basics when it happens: spark, fuel and air. Compression is likely not a possibility. You have to "catch it on the act," you know what I mean?

It may be losing fuel or something about spark advancing/retarding, but could also be some vacuum leak that happens intermittently? A scan tool with Live Data is a MUST on these type of problems! Fuel trims is what I would check. Ideally should be < 15%+\- on the long term. If both banks are lean or rich, then likely a fuel delivery problem.

Also check all other sensors and their output values obviously, such as MAF, TPS, MAP, O2s, etc. Good luck.

I had the codes scanned twice, the first time there were 7 of them so I cleared them out and drove two more days and the only one that popped up was the PO1345 code which is the crank/cam correlation code.. More than likely the timing is off. So I have a buddy that has the right scanner to check the retard on it and I will give you guys an update after I see him.

 

[Schurkey]

My 99 Yukon randomly bogs down when trying to get up to cruising speed, it usually starts around 50mph or so. I have to ease off the gas or take my foot off completely, if I give it gas it acts like it's starving for fuel. It usually takes about 10-15 seconds to clear itself out and when it does its like a flip of switch and then it's fine until the next random time.

What is the fuel pressure when driving?
How old are the spark plugs/plug wires/cap/rotor?

As said, a REAL scan tool would be a huge help. Look at the data stream including misfire history.

the only one that popped up was the PO1345 code which is the crank/cam correlation code.. More than likely the timing is off.

Changing the crank/cam correlation does NOT change the timing.

Timing info is taken from the crank sensor, not from the distributor position.

 

[EastOfGratiot]

I chased a bog problem for months before discovering it was due to excessive exhaust backpressure - partially clogged cat converter.