hey guys, so I’ve noticed that I get what seems to be an intermittent hesitation only* under load and light throttle 10-25% throttle, most times I can only feel it lightly surging when the conditions are right however a couple of times it’s very noticeably hesitated and cut out… I’m thinking it’s the fuel pump but really can’t seem to figure out a way to viably test it. Maybe I’ll replace it for PM. Seemingly this issue started out of nowhere with no known changes other then (1) cyl1 misfire a few weeks ago but it hasn’t come back and isn’t a pending fault. I am going to clean TB and MAFS this weekend but my gut tells me it’s neither of those components. If I should go to techstream what should I be looking at? Fuel pressure when conditions are met to duplicate concern? Thanks for any insight!
Hesitation no CEL (1 Viewer)
- Thread starter rckymtngx
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It could also be an electrical connection. Recommend checking the connections on the MAF and the throttle body when you clean them. You can clean them with connector cleaner (CRC makes a product for cleaning these
and install some dielectric grease on the connection. Mine had the same problem, but occurred when I'd drive through water. Turned out it was the throttle body connection - possibly a bit of corrosion/water in it.
EDIT: I've also had a MAF go bad; luckily a new OEM Hitachi MAF is not expensive. Plus I had a MAF connector go bad. If you have an OBDII bluetooth reader and something like Torque Pro, you can watch the MAF readings vs. time. It should be around 4.5-5.0 grams/sec at idle. If it's significantly different than that you might have a MAF problem. The MAF never caused cutting out for me, just weird idle speeds and codes. The cut-out seems more like a throttle body problem to me, although the misfire is a bit of a question. I know the coil packs on these can also go bad - a healthy 2UZ should never really have a misfire otherwise.
and install some dielectric grease on the connection. Mine had the same problem, but occurred when I'd drive through water. Turned out it was the throttle body connection - possibly a bit of corrosion/water in it.EDIT: I've also had a MAF go bad; luckily a new OEM Hitachi MAF is not expensive. Plus I had a MAF connector go bad. If you have an OBDII bluetooth reader and something like Torque Pro, you can watch the MAF readings vs. time. It should be around 4.5-5.0 grams/sec at idle. If it's significantly different than that you might have a MAF problem. The MAF never caused cutting out for me, just weird idle speeds and codes. The cut-out seems more like a throttle body problem to me, although the misfire is a bit of a question. I know the coil packs on these can also go bad - a healthy 2UZ should never really have a misfire otherwise.
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- Thread starter
- #3
It could also be an electrical connection. Recommend checking the connections on the MAF and the throttle body when you clean them. You can clean them with connector cleaner (CRC makes a product for cleaning these
EDIT: I've also had a MAF go bad; luckily a new OEM Hitachi MAF is not expensive. Plus I had a MAF connector go bad. If you have an OBDII bluetooth reader and something like Torque Pro, you can watch the MAF readings vs. time. It should be around 4.5-5.0 grams/sec at idle. If it's significantly different than that you might have a MAF problem. The MAF never caused cutting out for me, just weird idle speeds and codes. The cut-out seems more like a throttle body problem to me, although the misfire is a bit of a question. I know the coil packs on these can also go bad - a healthy 2UZ should never really have a misfire otherwise.
What’s making me think it’s the pump is the fact it only does it at a specific throttle amount that I cannot exactly determine, I want to say when it’s cold it the issue is much less noticeable if not gone entirely.
Fuel pumps on these are pretty reliable and not failure prone (no reported failures on this forum that I'm aware of). I'm also not sure if they'll cause a misfire code either. Nevertheless, you can fairly easily do a test with a fuel pressure gauge to confirm the fuel pump is not an issue.
There is no pressure port, I had to install a combination of these three items in the fuel rail, with some fuel-safe thread sealant. I've just left it on the fuel rail as a permanent feature. I ended up testing fuel pressure two separate times to rule out my fuel pump (first being the MAF/MAF connector, second being a bad batch of reman injectors) using a cheapie HF fuel pressure gauge.
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You could also swap the No. 1 coil pack go a different cylinder and see if the misfire code moves there. If so then I'd order a new set of coil packs.
There is no pressure port, I had to install a combination of these three items in the fuel rail, with some fuel-safe thread sealant. I've just left it on the fuel rail as a permanent feature. I ended up testing fuel pressure two separate times to rule out my fuel pump (first being the MAF/MAF connector, second being a bad batch of reman injectors) using a cheapie HF fuel pressure gauge.
Amazon product ASIN B000CPJI8IAmazon product ASIN B0081TJO72
You could also swap the No. 1 coil pack go a different cylinder and see if the misfire code moves there. If so then I'd order a new set of coil packs.
- Thread starter
- #5
The issue is I cannot get the misfire to duplicate, it was a one time thing that I’m not even too sure is related to the hesitation which is what’s got me stumped.
- Thread starter
- #7
No, AC Isn’t running always, and there have been times where it’s cut out as if it wasn’t getting fuel or spark in addition to intermittent hesitation. I know @Rednexus says fuels pumps aren’t common but it seems they aren’t uncommon after 200k and I’m at 235k, full throttle there’s no issue, half throttle no issue, it’s really only noticeable when I accelerate uphill/load while in a high gear with just enough throttle to keep from kicking down a gear in the 1800-2200 RPM range. I am going to spend some time this weekend to attempt to duplicate and record it.
No fuel/spark "feel" is exactly what I noticed with the throttle body connector. The easiest way to do this is start checking items off the list - check your fuel pressure, clean/check/grease the MAF and throttle body connectors, move coils around, etc. The connector clean/grease takes <5 min per connector, One by one, eventually you'll check enough things off the list and find the issue.
- Thread starter
- #9
Did all of those things and everything seems to check out however the problem still persist. I need to start checking other connectors or sensors I suppose. After driving for a while it’s getting bad, like foot on the brake and applying throttle it sounds like a damn misfire, but none appear to be happening. Please ignore the exhaust leak am waiting on headers currently.
- Thread starter
- #11
I did notice some of the rubber boots around where the seat to the plug are cracked, but the fact they aren’t showing up even when I’m live monitoring have had me thinking otherwise… maybe I’ll just do them, however it only does it after it’s gotten hot/warm more quickly if I am in stop and go traffic…
If you pull them I'd also check the plugs, and go ahead and do a compression test to rule out internal engine problems.
EDIT: You might also want to cross-post this on the 100 series forum. There are a number of guys over there who are true experts on the 2UZ-FE that we share with the hundy's. I know the simple stuff on mine but luckily haven't had to do a deep dive on anything more than troubleshooting sensors and electrical connector gremlins (which were all of a pain but quickly/cheaply resolved once I eliminated various sources of the problems).
EDIT: You might also want to cross-post this on the 100 series forum. There are a number of guys over there who are true experts on the 2UZ-FE that we share with the hundy's. I know the simple stuff on mine but luckily haven't had to do a deep dive on anything more than troubleshooting sensors and electrical connector gremlins (which were all of a pain but quickly/cheaply resolved once I eliminated various sources of the problems).
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Misfires are possible without a CEL. If they are getting worse when the engine is warmed up, it could point to a coil that is getting weaker (once had this exact problem on a 3UZ).
Here is how to check for misfires in Techstream. It will show which cylinder has the problem, even without CEL. You can then switch around coils to see if the problem moves with that coil.
Here is how to check for misfires in Techstream. It will show which cylinder has the problem, even without CEL. You can then switch around coils to see if the problem moves with that coil.
I have been having hesitation for a little while and couldn't figure it out. Well I was heading to the store and boom the Gx went into limp mode with CEL and other usual lights. So I pulled over and used my scan gauge and got a P0357 code which is the equivalent to p0307 and turns out it was the coil in the #7 cylinder. I ordered the appropriate part installed it, cleared the code and good as new now. I think I'll be ordering a trail spare coil though because when they go you aren't getting anywhere fast that's for sure. Thanks for all the help over the years MUD community. 
one banana job
one banana job
