<FONT face="Arial, Helvetica, sans-serif">Okay, guys, I need some serious help troubleshooting a problem that's popped up in the last MONTH (never occurred throughout vehicle's history)..</FONT></P>


<FONT face="Arial, Helvetica, sans-serif">Vehicle (basics here): 1997 4Runner 4WD SR5 manual.~135K.</FONT></P>


<FONT face="Arial, Helvetica, sans-serif">Problem: SERIOUS loss of power on inclines &gt;2% grade, 5th gear most notable, but power loss also noticable in direct proportion to equivalent higher grade/lower gear (now becoming really noticeable in 4th gear too)....verydistressing (off-road of course more noticeable..torque still good, though). For 1st time ever, in 5th gear, now must downshift on normal FHWA freeway grades. With pedal to floor will still lose AT LEAST 10-20mph climbing 'pathetic' grades (used to be able to accelerate through ascents). SUBSTANTIAL loss in MPG (used to be running about 280 miles to the tank about a 1 to 1.5 month ago, last down to 240...today have noted that I'm at 110 miles on the 1/2 tank!!! (rapid and consistent decline here is stressed). </FONT></P>


<FONT face="Arial, Helvetica, sans-serif">Just this past saturday, replaced air flow meter (was in pretty bad shape...) and cat converter (was about to die - at the very bottom of it's performance tolerance range...was starting to internally disintegrate). Have in the past month replaced fuel filter &amp;air filter. Spark plugs/wires fine &amp; dandy and relatively new anyway (replaced about 10-15k miles ago). Compression's good. No obvious, ugly, and interestingnoises to report. Engine clean as a "whistle"...every oil change, clean. Clutch getting a little sloppy with age/use (and a little more 'cranky' when cold...), but still within factory tolerances at the moment. Engine as of late starting to sound like it's working much harder under normal conditions...have noticed (at cold start) RPM running higher than usual (ambient temperatures pretty consistenthere, warmer in fact than where I was living/driving previously...notice that RPM from cold start now ~1,500 rpm (used to be consistently about 1,100-1,200 rpm) until vehicle warms. Regardless, RPMs still settle down to about 700-800 or so at idle after engine warms. No overheating problems. Not failing emissions. Don't tow anything (never have). Have been trying to chase this problem down...took it to Toyota...they're pretty much fishing in the dark - they haven't got a clue what's wrong (said "air flow meter and cat should DEFINITELY have solved the problem"). Neither one of us could believe it, but performance/mpg actually decreased further after the replacement leading to the obvious conclusion that these components (although necessary to replace) are and were not remotely the cause of the recent power loss/fuel MPG problems... whatever is wrong is still in disrepair and continuing to deteriorate at a consistent rate...am pretty confident that one day soon the check engine light will be popping up.</FONT></P>


<FONT face="Arial, Helvetica, sans-serif">Given these symptoms, has anyone out there had some similar experiences/direct knowledgethat might shed some light on my problem? I'm very interested here in what you did to resolve the problem. Looking for permanent &amp; reliable solutions. Not looking for temporary Band-aids, so please don't bother with seemingly "obvious" recommendations for things like aftermarket air filters (that wind up coating air flow sensors with the oil that is placed on them to compensate for the particulate blow-through), hi-tech spark plugs (that result in "more efficient" burning of fuel - aka, more energetic fuel ignition exceeding stock engine design tolerances later damaging cylinders, valves, etc.). The engine has remained entirely stock since I first purchased it, and this rig has been an incredible and consistent performer off-road.</FONT></P>


<FONT face="Arial, Helvetica, sans-serif">I have a sneaking suspicionthat these problems are the result of a dying clutch, or it's some stupid and seemingly inocuous part I'm overlooking that's failing and causing all this grief...in other words, I have the feeling, I'm chasing the "ripple effect" here (and definitely don't trust the dealer techsto do anything except gladly lighten the load of my wallet). Anyone with a story to tell/solution to offer? HELP!</FONT></P>


<FONT face=Arial>cheers</FONT></P>

try the 02 sensor <IMG src=smileys/smiley2.gif border="0">

Nope..</P>


O2 sensor didn't help. Replaced that as well. Still having substantial (and consistent) power loss problems. Had master service techs from Toyota dealership also take a peek at the valves and perform a dry/wet test to see if any valves/rings were going out. Perplexing data obtained. Based on data alone, appears that rings are going bad (as shown by the wet test results); HOWEVER, based on the results, also indicates that valves at minimum are performing at 80% normal. Two of the worst are performing at 60%. Techs don't buy it at all - said that at these levels, the engine would NOTICEABLY be running rough (which it doesn't - runs quite smoothly) and ride would be terrible (which it's not); just losing power on inclines and rapid accelerations - engine is taxed. Dealer recommended replacing the engine entirely for cost-savings. Still, this is quite a bitter pill to swallow and I've fully lost faith in their ability to accurately diagnose the problem since it's clear they're guessing now.</P>


What is the 97 4Runner engine's response to clutch wear? Clutch is definitely getting sloppy... Have had power loss problems on other manual shift cars before that turned out only to be the rusult of a dying clutch. replaced the clutch, power came right back. Have explained this to the techs, but they're already confused about the problem and don't really have a response to this. Don't have a problem with replacing the engine if warranted, but also do not intend to just toss money at it if the valves/rings aren't the problem at all.</P>


Thanks again for the advice.</P>

I actually stumbled on this forum while trying to research the exact same problem I had with my 98 SR5 five speed w/ 120k miles. Severe power loss and mileage loss. Any attempt to exceed 3000 rpm was comical. I printed out the original post to my mechanic plus some other information I had gathered to help narrow the problem down and he was able to determine what was wrong by the next day.

The problem was that the timing belt had slipped and one of the passenger side camshafts was off 25 degrees. When I had my timing belt replaced @ 95k miles, the dealership did not replace the tensioners. My mechanic handed me a toothed shaft where one of the teeth was sheared off and explained to me that there were upgraded parts specifically for this problem and that they also should have been installed. The timing belt, belt idler, belt tensioner, water pump, thermostat, cam idler pull, roller pulley, and crank pulley were replaced. The vehicle feels almost the way it did when I first got it. I feel confident in saying that this 4Runner has pretty good power for it's mileage now.

Needless to say I'm very displeased with the dealership, and I'm glad that I took my 4Runner to a trustworthy mom & pop garage instead. This type of repair would have cost me quite a bit more than $1100 at the dealership, which unfortunately would not be necessary had they not screwed up to begin with.

While I still curse the people who stole my 94 Supra twin turbo four years ago, this 4Runner may be the very best vehicle overall I've ever owned. Since you described my problem exactly, I hope this information is useful to you or someone else.

Funny I just joined on to this site and WOW - I thought the power loss and bad gas miliage was because it was an older car 92 4Rnr w/ 160K. Guess I'll have my trusty neighborhood mechanic chech out some of the things mentioned above. ALthough, higher octane gas helps a bit.</P>


Also, I posted the following in another thread, but, if anyone can help pease reply.</P>


I have a 92 4Rnr and recently had an A/C compressor replaced. Now when the A/C is onI hear a whining noise that increases/decreases wirh acceleration/deceleration, almost mirroring the RPMs. It is annoying, I took it back to the A/C repair shop and they said they replaced the compressor 3 times. and the noise is still there (why would they look for something other than the compressor after the second replacement has me baffled). Anyways I took my 4 Rnr back and am having to deal with this abnoxious noise daily. Any ideas what this could be? Some have suggested pulleys, etc......</P>


THANKS</P>


</P>

i have a 98 runner with 145000 on it same problem! it was the coil packs. they start going bad after 100000. there is three of them at 80 bucks a piece. have you replaced them yet?

does the 92 have that belt tensioner below the a/c? if it does the bearing go bad in those and they will do that. on toyotas when you replace some thing the next weakest link in the chain goes out. 2 of my good friends work as a mechanic at toyota dealers and thats what they tell me. thats also why i bought a yota because if some thing goes wrong they fix it for free or cheap. <edited><editID>stevdra</editID><editDate>38570.8930787037</editDate></edited>

I had no power and low mpg. They replaced the coil assembly. Runs like new (1998 4 runner)

Hello lame blacksmith,
Anyway, how many miles are on the clutch? I bet your clutch is slipping. Better get it taken care of now. Marlincrawler.com has centerforce HD clutches for $275. It includes an HD pressure plate and probably the TO bearing, Pilot Bearing, and alignment tool. Anyway, check the clutch out.