HELP : Sudden Loss of Power Going On Overpasses

[eternalize]

On even slight inclines, I feel like I have no umph. Yesterday, I go over this overpass in Washington (Snoqualmie) and from overdrive it drops to 3rd (where normally it'd have plenty of power), now pedal almost on floor, it's giving me almost nothing, rpms won't budget at 2,500 rpm / 3rd gear, I keep slowing down to ~45mph (giving even more gas now), downshifts to 2nd and starts yelling at ~4,000 rpm. We get to flat zone and it cruises at 70mph no problem.

Inner city driving is fine, just takes longer to shift into next gear and feels "sharper" when shifting.

Until yesterday, I maintain ~60mph on this pass with no problem and when I have to pass somebody, I drop to 3rd gear for tons of power. Now I can't even pass a Camry going 60mph on flat highway without taking 30 seconds with my floor almost on the floor. Gives me no code, give me a bone to chew on at least *sigh*

1999 4Runner 3.4 5vz-fe 238,000 miles

Symptoms
- Loss of power on slight hills and especially overpass (to the point where I feel unsafe now)
- Coolant leak for a couple years (blows white smoke, goes away in ~3 mins, could be head gasket, but I top it off every two weeks, go through a gallon every month, I know I should get this checked out)
- Valve cover gaskets been sweating for years, BUT...
- No Engine Oil consumption (always 5.5 qt oil for every oil change for the last 60,000 miles)
- Sucking sound when manually opening throttle body coming from plenum area closest to firewall (if I flick it fast enough, it just sucks and doesn't even rev)
- Compression Check as of today:
C6 :: 195
C4 :: ~160
C2 :: 180
C5 :: ~190
C3 :: 180
C1 :: ~180
^Cylinder 4 has history of spark plug failure and causing misfire, I replaced this plug ~4 months ago and now when I pulled plugs to replace all of them yesterday C4 plug had oil from threads to the tip
- Ticking sound under front side of transmission bell housing on cold startups for ~3 mins until warmed up and it goes away ever since I had transmission replaced ~8 months ago

Diagnosing I've Done
- New dual tip iridium spark plugs as of yesterday
- Vacuum Leak Check by spraying MAF cleaner around all main vacuum lines in engine bay :: found one small leak on top and replaced to no avail (even after unplugging battery to reset)

Maintenance History
- New NGK plug harness 4 months old
- Oil change and filter 2,000 mi ago
- Transmission replaced ~8 months ago
- Transmission fluid pink and in operating levels
- PCV Valve and tube replaced with OEM and ~8 months old
- TPS replaced ~8 months ago
- Battery replaced ~8 months ago

Fuel Trim Data
- Long Term Fuel Trim around -4.5% on highway cruising speeds
- Coolant Temp 190-205 F (sometimes 210 when going up pass and struggling now)

Here's what forums are telling me I could do, but I want to pass them through you all first before starting tests:

• leak down test
• replace all vacuum lines since they're old and starting to crack
• clean MAF sensor
• fuel filter replace
• fuel pump replace or check fuel pressure
• air filter replace
• valve cover gasket
• some sort of valve adjustment maybe?
• head gasket problem (in which case, I don't even now if I should rebuild the engine or replace JDM, any recommendations from Seattle, Washington will be appreciated)

I am utterly lost, I've got to drive back to Seattle tomorrow from eastern washington and it's a 4 hours drive with hills, I'm scared it won't even make it.

 

[eternalize]

One more thing to note is that I've never had a sucking sound ever be present when engaging the throttle body manually with my thumb. Weird that it even comes from the back towards the firewall and even more alarming that my engine doesn't increase in rpms as it would normally when I flick the throttle body fast. Instead there's just this huge sucking sound and rpms only increase by a hundred or two.

 

[TucsonMike]

Is it possible the catalytic converter is plugged? My friend experienced a loss of power on his Camry and that was his issue.

Good luck
MikeM

 

[eternalize]

Could be the CAT, Ill do some digging if I can make it back today.

Problem got a whole lot WORSE a day after. I’m at -10% LTFT now trying to maintain 60mph on flat highway.

Coolant was getting to 212F so I pulled over. She is so so tired all of a sudden gah.

Idk if I should have her towed at this point

 

[heat]

Might be worth checking to see if the timing belt jumped a tooth or teeth.
A lot of other possibilities don't fit the "sudden" nature of your problem.
When's the last time it was changed?

re: towing. If it's not drivable, what other options do you have?

 

[Ben Dejo]

What RPM does it idle at? Do you have any codes present? Maybe check the clamps on the air intake hose, make sure they are tight and seated correctly. Check the air outlet hose from the IAC, to see if it has cracks or lose. Have you put a vacuum gague inline anywhere after the throttle body? That can help to determine if you have a vacuum leak. Its in the Haynes book somewhere. Have you had a cylinder misfire code yet? Its at the right age for a failing fuel injector, but that behaves differently than what you describe. LTFT is negative, so its subtracting fuel, but not to the point beyond normal for old engines. The longer you put off the coolant leak, the more likely it is to fail when you are towing something. The cat usually fails if fuel, oil or coolant is dumping through the exhaust for a long time.

 

[eternalize]

Update :: got worse yesterday as I was limping it 50 mi back from eastern washington. Parked in front of family's house at the moment. Calling a few shops. Coolant temps got up to 215 F so I took two breaks after a few tiny hills.

Timing belt has been around ~80,000 miles ago, so might be time for it.

RPMs at idle :: ~700 rpm

LFTF yesterday :: -10.7% on highway speeds ~50-60mph

No codes, clamps on air intake hose checked and tight and seated right. Haven't looked for outlet hose on IAC, but will do that soon.

Haven't done vacuum gauge at all, might be my next step.

Had cylinder 4 misfire in February but solved with new sparkplug :: this isn't misfiring (or at least misfiring horribly) on the freeway. Otherwise I would've felt it jerkin. I just seem to have no power and that engine is working super hard.

Could be the cat, but would that cause such a sudden failure?

Another possibility is the torque converter in my "new" transmission. Any chance that could be the cause regarding my situation? I'm not sure how old the tranny was that the shop put into my rig and the shop is going to definitely fight to not have to use my warranty, but I just want to know I have enough ammunition to throw at them in case it could really be the case.

I might take it over to the transmission shop for them to do some sort of vacuum test or something.

Can you even check if the Torque Converter went bad without dropping the transmission?

 

[Ben Dejo]

Your power problem and overheating are strong indicators of a blown head gasket. The problems will only get worse without addressing that. There are plenty of posts about head gasket problems. I would suggest starting there before assuming its the transmission. My 4Runner is a manual so I cant speak on the nuances of the automatic.

 

[3bears]

now that it has been a few days, are you noticing any fluid level changes like losing coolant ?
With your #4 being lower than rest I would do a leak down esp involving that cylinder
In my experience when it comes on quick with no warning its not the cat or fuel pump

 

[eternalize]

The other indicator that made me refer to the the transmission is that it's be sweating and I see drips of pink (likely tranny) fluid coming from where the transmission mates with the transfercase :: also was talking to a technician at TSL Automotive in Tacoma, WA :: a Toyota specialist :: that the ticking that started in during cold and went away warm could be my flex plate and something of a torque converter.

I left my rig in eastern washington and I'm back in Seattle with the old family van for now, old reliable Ted.

Going to have a friend tow it to Tacoma next week for a few benjamins and have TSL Automotive do some diagnostics. I'll keep everyone posted :/

I don't mean to get too ahead of myself, but I'm already thinking about selling it as is if the head gasket blew up.