Vehicle: 98 Acccord EXV6 non-CA emissions 300k. All stock. Last tune-up at approx 130k. Oem exhaust system still on car. In last 3-6 months have had "insufficient EGR flow" DTC, a Bank 1 or Bank 2 O2 DTC, and a cat DTC code...I think. They come and go. Check engine light has come and gone, too. Randomly I would reset the OBDII just to see what the recurrence rate was. Usually within 1-3 days the light would be on and one of the codes would be there.
-
More importantly, suddenly last week in my morning drive I accelerated and it was as if the fuel was shut off....not low power, but NO acceleration/power episodes between 50-65mph. Hold my foot to the floor and it would eventually revive and lurch as power came back for 2-10 seconds and then repeat. Only way to get back up to 65-70mph was to "pulse" the accelerator with my foot for sporadic acceleration. Originally,no probs below 50mph (around town, let's say)...and if I could get it past 60 or 65 it would resume normal behavior.
-
Now, it seems the problem-range of mph's for this power-shut-down is expanding above and below 50-65mph. Almost stalled once coming to a stop at an off ramp. Have notice some marked stumbling, though randomly and short-lived, at idle. Now too dangerous to put on the highway.
-
I know tune-up is way past due...and cat is likely on it's 9th life, BUT how do I differentiate and keep my costs down while getting my normal/typical performance back. May have 2 culprits here contributing, but I could do a tune-up after the fact if the cat will get me out of the danger zone on the interstate. Help?

Kevin

 

How many miles are on the spark plugs? Which spark plugs did you use?

Low EGR flow could be caused by a blocked EGR passage.

Watch this video on cleaning the passages.

 

You are due (170 k miles since last tuneup) for plugs, wires, and distributor rotor.

Supply actual codes (Pnnnn) to get best answers.

Converter may have been damaged by inattention to other issues and blocking exhaust, causing excessive backpressure. See following link for vacuum test to check for exhaust restriction.

BAT Auto Technical-Professional mechanics giving advice-An Educational Site w/ OBD2 Trouble Codes and Technical info & Tool Store.

good luck

 

"Vehicle: 98 Acccord EXV6 non-CA emissions 300k. All stock. Last tune-up at approx 130k."
-
Proper/prescribed OEM NGK Laser Platinum plugs.

 

Still no codes, curiously. Plenum and intake cleaned, and EGR drill-out and retro-fit with teflon sleeve done back at 175k with new EGR valve. I'm still curious as to anyones thoughts about complete shutdown of power between 55-65 (with this range now expanding s l o w l y). Can pulse accelerate throught with Much effort. Not a misfire. No power! Then a SURGE when I pulse the accelerator. (?)

 

Are you sure Check Engine Light is OK? Light should come on/go off when keyswitch first turned to ON.

First step should be basic tuneup items; spark plugs, wires, distributor rotor/cap.

If sure no codes, suggest some basic checks; fuel pressure, crankshaft/camshaft timing, vacuum check at idle and w/ quick throttle pulse.

If you have access to a obd2 scanner, check Long Term Fuel Trim at idle fully warmed condition. This may show a lean condition that does not meet code set levels.

good luck

 

When you get the bank 1/bank 2 codes, does the exhaust manifold glow red or become super hot early in the cycle? If so, I think you may have a plugged cat or resonator. I had a similar issue with a KIA V-6 where the cats were fine but the resonator was heavily plugged up. It would start and run and even drive down the road but after a few minutes, it would do exactly what you describe. The one I'm writing about was only about 10% free so the flow would bottle up after a few minutes. Too much back pressure was the result as was the bank 1/bank 2 code......sean

 

You have driven ~125K miles since cleaning the EGR port. It can clog again even with the sleeve kit installed.