Cold hesitation

[Dwight S]

I did a search but nothing came up that matched my symptoms.

The other morning I cranked my truck and let it warm up for a few minutes and then left for work. Within a 1/4 mile I stopped at a light and then started moving. I noticed a slight stutter/hesitation from off idle to around 20 mph. I was stuck in stop & go traffic for about 4 miles & 20 minutes. The hesitation continued each time I started to move. After I cleared stop & go, the hesitation stopped and everything seemed fine even at other traffic lights. At lunch, similar symptoms, stutter for a while then fine. Same after work and so on and so on.....

No check engine light. I filled the tank the day before it started. I'm running a high concentration of Lucas Fuel Treatment to see if it's something simple, but no luck so far.

Don't have a scangauge, probably need to invest in one.

Does anyone have any thoughts on what it could be?

Thanks for any help ya'll can give!

 

[ToHiHy]

Put some gasoline water removal/antifreeze in your fuel tank. Sounds like you might have a bit of water in your tank. Fuel filters do that too if they haven't been changed in awhile. Throttle body clean?

 

[2001LC]

Bad fuel a real possibility. Did you notice fuel truck filling storage tanks while you got that gas, they can stir-up sediment.
Seeing any smoke out exhaust?
I do like BG products like 44K treatments, does a good job from tank to O2's get those fuel injectors opened up as well.

Sometimes hesitation issues are just a bunch of little things accentuated by bad gas. I'd certainly do a tune up if it's been awhile.

You most like know this stuff but worth repeating. Some items will have nothing to do with your issue, just best practice:
Check coolant level, should be at cold mark (cool dn overnight). If low need to find out why.
Check weep hole of T-belt cover for oil or coolant.
Warm up engine and transmissions. Drive is operating temp & oil pressure normal
Check transmission fluid level, color & smell. I do full flush ~15 to 20K miles.
Check valves adjustment (by sound)
Air filter; clean and good seal in box.
Make sure to disconnect battery for 30 minutes, this is a must to reset for MAF cleaning.
MAF spray cleaning.
Clean T-Body.
Check PCV valve, grommet and hoses.
Check all vacuum lines.
Reconnect battery after cleaning & greasing post.
Fuel filter is Not a Toyota rec. maintenance item, but I do swap out ~80K mile.
Check all coil, wires & plugs.
Check & change oil and filter. (check color & smell)

Hope it's not more pricy stuff like bad injector, coils, TB etc..

 

[Dwight S]

Thanks for the ideas. I filled up again this morning with premium gas and dumped in about half of a large bottle of Lucas fuel system cleaner. Should know better in a day or so if it was bad gas. I am about due for spark plugs. Need to replace fuel filter too... I'll update as I figure it out.

 

[Dwight S]

Finally, an update.
I did all the regular easy stuff like cleaning throttle body and fuel system cleaner with premium gas. But nothing seemed too improve. But it didn't seem to get worse either. I even bought a Scan Gauge II to see if I could get any codes. Nothing....

Last night I left the hospital where I was visiting my mother and when I got on the road I noticed more hesitation and stuttering. I pulled away from a light and gave it a little more gas than usual and the stuttering got worse and the check engine light started flashing. Drove the 65 miles home with constant stuttering and flashing CEL. When I got home and pulled the code, up popped P0301. This morning i pulled the coil and swapped it with #2 and checked codes again and this time it was the 302 code. So, off to AutoZone for a coil pack. Only place locally who had it in stock. Figured lifetime warranty and a decent price, do it and get back on the road... Replaced the coil and the truck is very happy.