BuickGirlFromMars
SUPER STAR!
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- Buick Ownership
- 1999 Buick Park Avenue Ultra (Supercharged) , 1977 Buick Electra Limited (350 SBB)
Yes, I would lean towards ignition assuming the MAF Is a Hitachi or Delphi(Is it?)
Glad its better than before
Also the gas cap warning can be quick to pop up or it can take time it depends on fuel lvels, pressure readings, temps when turned off and on, when the system does other checks etc etc.
Actually, you mentioned that gas cap and weird fluctuations especially
"Looking at my fuel trims in real time crusing down the freeway one seems to really try to compensate for something"
so this is only cruising? Not other driving?
I would look at your Evap system purge valve for proper sealing and operation and mind you EGR is supposed to be working such that EGR flow is at its peak during steady cruising under moderate load.
sO your block off plate ,whatcha doin with that? EGR blocked, but the pintle is still moving because of PCM commands? Hows the seal? Did your PCM get tuned to not have EGR functions and the pipes were plugged and confirmed they were not cracked, split, or not sealing well becuase those sheet metal tubes are not very cooperative even if you never touched them, they are still made and not expensive but annoying to get the back one usuaully for sure. The early 3800 series 2 l36 also had issues with the sealing at the plastic intake. Basically, blocked off, you have 20 inches of mercury or something yanking on something barely stronger than old carbureted car stove pipes for the THERMACs on the air cleaner. The slinkie stuff. Or dryer vent stuff, that stuff doesnt like to cooperate either and its larger diameter. Perhaps would promote leaks esp with time.
Let us know whats the hu-bub with the EGR and check your purge valve You could try unhooking the valve and plugging the vacuum port to the TB On the TB. That would make the computer 1) not expect to use Evap purge for AFR calculations 2) not have any leaky gas or etc to change Same boat as the EGR basically.. If your car isnt seeing EGR valve and Evap purge valve, it cant errouneously correct for things that may be wrong with them but that doesnt guarantee things run better keep that in mind.
Check that ICM, check your PCV, check your Purge, let us know on EGR, let us know your MAF, when did you replace the first oxygen sensor? Show us a pic of the back of the engine from the top so your oxygen sensor and plug wires are visible and then one from the front for the plug wires and purge valve
Also have your battery load tested and your alternator checked.An alternator could have issues at that speeds because ignition system is demanding more and heat hates ICMs a lot like it hates alternators. Thats free and easy and its still not 100% but im trying.
There is an uncomfortable truth im about to share with you, other than the lean data we see over long term which, assuming its correctable, the behavior of the car on the cruise/highway is something that is magnified by driveability issues in 4, so try 3. But the uncomfortable part is the hyper focus on the fuel trim and the vigilance for the issue, you could continue to mistake a possible normal behavior as well as be a combination of not -trans things that seems to be 1 single thing. Chuggle. Fishbite.
If your TPS was OE, consider that a possible thing and put a new one on if you have it and make sure to properly install it on the butterfly thing.
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| Engine Controls - Intermittent Chuggle/No DTC's Set Bulletin No.: 05-06-04-058 Date: September 07, 2005 TECHNICAL Subject: Intermittent Chuggle or Fishbite on Light Acceleration or at Highway Speeds with No Diagnostic Trouble Codes (DTCs) (Replace Throttle Position (TPS) Sensor) Models: 1995-1999 Buick Riviera 1995-2004 Buick Regal 1995-2005 Buick LeSabre, Park Avenue 1997-2005 Buick Century 1995-2001 Chevrolet Lumina 1995-2002 Chevrolet Camaro 1995-2005 Chevrolet Monte Carlo 2000-2005 Chevrolet Impala 1995-1997 Oldsmobile Cutlass Supreme, Ninety Eight 1995-1999 Oldsmobile Eighty Eight 1998-2002 Oldsmobile Intrigue 1995-2002 Pontiac Firebird 1995-2003 Pontiac Grand Prix 1995-2005 Pontiac Bonneville with 3800 V6 Engine (VIN K - RPO L36) Condition Some customers may comment on an intermittent chuggle or fishbite on light acceleration or at steady-state highway speeds (typically 80-105 km/h [50-65 mph]) with no PCM DTCs set. This condition may lead the technician to suspect the TCC circuit or torque converter.[no PCM dtc means that theres no DTC that would cause it, a small evap leak code wouldnt be that for example.] Cause This condition may be caused by intermittent operation of the Throttle Position (TPS) Sensor. Correction In observed cases, the Tech 2(R) is not fast enough to consistently detect this condition during a snapshot. It is recommended to use a DVOM set to the min/max recording mode. Connect the DVOM at the TPS connector (positive lead to TPS feedback signal pin and negative lead to TPS ground pin). Duplicate this condition by driving the vehicle. If the voltage dropout (less than 0.45 v) is recorded on the DVOM, replace the TPS sensor and re-evaluate the vehicle before continuing with other driveability or transmission diagnosis. |
