Symptoms of bad gas or clogged filter?

[oakback]

I'm getting real hard misses, sledge-hammer-to-the-drivetrain misses, occasionally. Happens under throttle, more obvious when accelerating under load. Idles fine.

It seemed to start 2 days ago when I ran my tank lower than I ever have before, then emptied 4 or 5 gallons from a gas can at home into the tank. The gas was a few months old. Could this cause the hard misses?

No CEL codes yet.

 

[2001LC]

Typical clogged fuel sock and or filter, results in BK1 & BK2 lean fuel trims (FT). This shows up as long term fuel trims above 5% while cruising at 60MPH on flat HWY, throttle steady.

Under load misses, are often bad or weak coils (COP). They'll seems like a torque converter or AT issue. Not usually a what I'd think of as: "sledge-hammer-to-the-drivetrain"

I'd:
Check AT fluid level.
Run down/out gas tank, to empty (~40 to 50 miles after low fuel light). Fill tank with fresh gas and 2 cans of 44K. Avoiding fueling station with old metal tanks.
If issue not cleared up:
Check FT, ECT (engine coolant temp) and ATF temp, while on HWY cruising.
Use TechStream to look for misfires.

 

[oakback]

I don't have tech stream (or a laptop), but I'll try the other stuff.

So far ECT and trans temps are good on my OBD bluetooth reader. And I've had plenty of bad coils in the past, it feels similar but much more harsh/hard/violent. But I've got 2 spare coils on standby for when/if the misfire code is thrown.

 

[2001LC]

Most bluetooth OBD readers, read FT. A valuable reading! I had one were engine was tuned perfectly. Yet LTFT ran 7% best. Found rust in fuel tank, sock an fuel filter. Cleaned out tank and R&R fuel pump , sock and filter. LTFT 0 to 3%. But never did post condition causing missing or bucking.

To say "AT temp & ECT good", means what? AT temp what and at what OAT, road and weather condition! Some feel 210f ECT is good other think 145F is good. They're not.

If "plenty of bad coils in the past", on this engine. I'd question coils. Real Denso or Toyota Denso COP, rarely go bad. Unless subject to unusually high heat, spark plugs have walked out and cooked coils or gap in plugs to wide for to long.

You'll not get a DTC (CEL) for weak coils, that are just misfiring when under load. Not likely even a pending DTC.

 

[oakback]

You're right, I dug through the OBD app and found the following, which one is best applicable?
fuel trim bank 1 long term, fuel trim bank 1 short term, fuel trim bank 2 long term, fuel trim bank 2 short term, fuel trim sensor1, fuel trim sensor2 (and so on to 8).
edit - nevermind, those display options are there, but they all say "no data received", so it won't show me anything.

Ok, what should AT and ECT be? You're right, I don't know what's good. I thought under 210F was generally ok, but clearly I'm not an expert.

I had coils start going bad after I purchased the vehicle, I don't know what brand or age they were. When one would start going bad, I'd feel the misfire. After a while it would trigger a check engine light with a code for the cylinder containing the misfire. Rather than replace all of them, I'd wait for each one to go bad (short on funds at the time). I'd carry a spare, and when I got the code for the cylinder with the misfire, I'd pull over and swap it, then buy 1 more coil. The extras I have are cheap brands, I can't remember how I ended up with them. But they'll do fine as spares to get me where I'm going if a coil fails again.

This current issue doesn't feel like any of those 8 failing coils, but I could be wrong.

 

[2001LC]

You're right, I dug through the OBD app and found the following, which one is best applicable?
fuel trim bank 1 long term, fuel trim bank 1 short term, fuel trim bank 2 long term, fuel trim bank 2 short term, fuel trim sensor1, fuel trim sensor2 (and so on to 8).
edit - nevermind, those display options are there, but they all say "no data received", so it won't show me anything.

Ok, what should AT and ECT be? You're right, I don't know what's good. I thought under 210F was generally ok, but clearly I'm not an expert.

I had coils start going bad after I purchased the vehicle, I don't know what brand or age they were. When one would start going bad, I'd feel the misfire. After a while it would trigger a check engine light with a code for the cylinder containing the misfire. Rather than replace all of them, I'd wait for each one to go bad (short on funds at the time). I'd carry a spare, and when I got the code for the cylinder with the misfire, I'd pull over and swap it, then buy 1 more coil. The extras I have are cheap brands, I can't remember how I ended up with them. But they'll do fine as spares to get me where I'm going if a coil fails again.

This current issue doesn't feel like any of those 8 failing coils, but I could be wrong.

By now you should have old gas out and a new tank of fresh gas. So any change?
What are you FT reading?
What are your ECT & AT readings?

ECT 184-187F 98-02 w/condenser fan, OAT up to 100F, AC on, touching on 191f at stops lights, but back down fast.
ECT 98-99, 03-07 W/O condenser fan, same as above up to OAT of ~68F, over 68F - ~100F OAT full sun, 192-197F touching on 200f but back down fast.

AT #1 ~125F -165F up to OAT of ~100F, no ext. load. Make sure level correct at ~160f (158f to 176f ) AT #1 temp. Use a good fluid. I like 12 qts of fresh Mobil 1 MV ATF full flush, for the 98-02.

P03-- DTC: Don't often come up, with a weak coil just misfiring under load. They do come up with bad/dead coils, plugs or wires. Since you've been getting P03--, with the coils in engine. I make sure to replaced all, with Denso or Toyota.

I use either Denso or Toyota Denso coils, I buy from Denso distributor or Toyota. Never from parts store, ebay or Amazon. As just to much junk and to many bootleg from China in the market. They range from $58 to $110 each. Anything less, is likely junk!

 

[oakback]

I've been through plenty of gas and fuel treatment now. Temps are within those specs (without changing any fluids). I don't have a way of measuring fuel trim.

Symptoms have changed a bit. Now when it's fully warmed up, I get nothing odd. But when cold it misfires a lot. Under hard acceleration I hear feedback in the stereo that wasn't there before (ticking that seems to coincide with RPMs).

Still no codes other than failed/disconnected O2 sensor, I've been running with a failed one because I can't remove it without removing that portion of exhaust, and it's my daily driver so I've been putting it off. Not sure if that could be a contributing factor.

 

[2001LC]

I had one, that misfired cold. It turned out to be an aftermarket coil.

Bad o2 is and issue, that tosses a monkey wrench into the mix. All system need to be working as designed.