So, I searched thru the forum/threads to see if this has been addressed. Can't find it. Here's my issue:

'05 5-spd w/196K miles. In the past few months, I've been experiencing a very noticeable drop in power/acceleration as I'm rowing up thru the gears at around 3700 - 4000 rpm (in each gear). I mean, as I'm throttling up, it's like someone has got a giant hand on the front of my car...holding it back. The XMSN has just been rebuilt recently but I noticed it before that. I have no engine codes and the car is otherwise fine. I've had the car since 140K and I've never messed with plugs or coil-packs, fuel filter or injectors. I'm hoping to tap into the wealth of xB-1 knowledge from you fine folks. So, any thoughts?

 

You are on the right track - try the plugs as they won't throw an engine code that I'm aware of.
If you get new plugs make sure they are iridiums. Standard plugs burn down fast in this engine (30k miles or so)

 

Hey Rich. Thanx for the reply. Any recommendation on brand?

 

Preferred plug seems to be the Denso IK16 Iridium Powers with a 0.044" gap (you might want a different gap but this falls in Toyota specs) and torqued to 13 lbf⋅ft. Some people use anti-seize on plugs and others don't...I use a nickel-based anti-seize because, well, steel plugs into aluminum heads.

 

Thx! $4.16 ea. at Rock Auto.

 

I think you should try the plugs 1st. But I thinking if the plugs aren't it I think its a fuel issue. Does it happen when you rev it while its sitting? Have you checked the air filter? What have you ruled out?

 

No. It's fine when revving. Air filter's good. New plugs seem like an easy, cheap starting point.

 

I was editing my post and I got sidetracked lol. I agree the plugs are a good place to start. What happens above 4000K rpm?

 

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>4000 rpm? Wellll, by then I'm doing 75-80mph and all 105 of the little horses are screaming. Lol

 

Lol but does the power come back? In my tuning it I loose spark going that fast the motor just goes to completely 0 and that's very noticeable lol when I've run out of gas it like you could just press the gas more and nothing happens but the motor is still going, like its only able to sustain what it was doing.

 

Yeah. After 4k, I'd say what-passes-for-power is back.

 

hmm alright. let us know the gap of the old ones when you change them im curious.

 

Ok. Will do.

 

When it comes to reviews, I read them, but tend to place more weight in reviews of stuff here (ScionLife) than other places. Over on Amazon, Denso IK16 got kinda trashed by people. What's y'all's take?

 

I don't know what reviews you're looking at...they've got 4.5 stars, give or take, while NGKs also have 4.5 and Bosch and E3 have around a 4-ish star rating. The two negative reviews I saw when glancing at them were for someone who got the wrong plugs and someone how ordered the plugs and they didn't fit his car. Not exactly what I would call "trashed."

Did you search on here as that's what prompted me to go with them in the first place.

That and you said they're $4.16 ea...not really worthy of hours and hours of reading reviews.

 

UPDATE: So, I've changed all the plugs with Denso IK16, gap at 0.044 (which is what they came set to). I checked the old ones upon removal and they all looked a little blackened and were pretty much at about 0.044 except for one which was about 0.049. No biggee. I ran a couple bottles of Lucas FI cleaner thru a tank or two just to see what would happen. Plot twist - my wallet got lighter.

The issue is still there - a VERY noticeable decrease in power. Now, I can feel it at low speeds. Another thread mentioned a Vacuum Leak. How do I check that?

1) Coil packs?
2) Vacuum leak?
3) Fuel Filter?

Thanks. Y'all are awesome.
Scott

 

Easiest way to check for a vacuum leak is to run some Seafoam through your system.

bad news on the fuel filter is that I believe it’s built in to the fuel pump, which would require a fuel pump replacement. Clean your throttle body. Carbon buildup in a throttle body could cause a “flat spot” in the throttle. Also light want to replace your VVTI console pod as well (It’s a relatively cheap sort, around $22-$35). The vacuum lines are relatively easy to replace as well. Hard part would be a vacuum leak due to a faulty intake manifold gasket or throttle body gasket.

 

What would seafoam do to pinpoint vacuum leak?

Follow-up on plugs, new Denso plugs come with an anti-friction coating on threads. So fresh 1st install, put them in dry. But 2nd time around, should use anti-seize.

 

Gotta be better than cigar smoke.

 

Hey dude so check for a vacuum leak get some starting fluid and mist around the two vacuum hoses coming from the valve cover.... one goes directly back into the intake so thats easy... and around where the intake manifold fits to the engine. if its sucking air and sucks in some ether its gonna rev up a bit.

Also I suggest you clean your MAF if you haven't. You could remove your fuel pump and see if there is any junk in your tank that would suggest a clogged filter