95 camry loosing power

[camry4ever]

I have a 95 camry (4 cyl, 5sfe) with 186K miles. It used to run great however lately, it seems to have lost quite a bit power and does not accelerate as quickly as it used to do. The power loss is more noticeable when driving uphill. The fuel consumption has also suffered with about 300 miles/tank (16.5 gal.) of city driving. The vehicle has been very well maintained though-out and engine still runs fine without any abnormal noise or other visible problem. Please note that sp. plgs, plug-wires, air-filter, timing-belt, etc have been replaced lately. The vehicle also passed smog inspection, hence the exhaust system issues can also be ruled out. Engine idles/runs great without any missing and timing is also fine. Compression (cylinder) looks good too (185-165-165-185). Note that it still has original fuel filter and per dealer, camry fuel filters are good for the life of the vehicle and need not be replaced. May be at 186K, it is time to change it.....
Any tips/insight as to what is causing the power loss will be greatly appreciated.

[JennyDee]

I would suggest that you run a self diagnosis test and jump TE1, E1,car in neutral, and ignition switch is ON with engine not running. See if it gives you and codes, which will help. Haynes Repair Manual has a chapter on this process or you can get it on this forum under the Manual section.

It still can be a oxygen sensor as the ECM will operate in what they call and open loop mode if the O2 sensor is not giving it the proper signal.

Keep us posted.

[RIP]

What was the last maintenance you performed prior to this starting and how long before? Was the engine warm when you did the comp test? Did the pressures build up quickly or did it take a few revs to get to normal? How's the fuel pump pressure?

[camry4ever]

Appreciate the responses.
I forgot to mention earlier that CHECK ENGINE warning light has never come on when the engine is running. My understanding is that the CHECK ENGINE light will come on if ECM detects any anamoly. Therefore, I doubt if any diagnostic code can be retieved. Pls let me know if I am missing something here and should still run diagnostics.
The compression check was performed when engine was cold and compression built-up pretty quickly (within two or three compression strokes). One thing worth mentioning is that one of the spark plug tubes seal leaked which resulted in some oil seeping in around the spark plug. Subsequently, tube was resealed and spark plugs and wires were replaced. As I stated earlier, the vehicle has been very well maintained thoughout. Fuel pump pressure has not been checked yet and I was leaning towards replacing the fuel filter if that sounds logical.

[DFBonnett]

You might want to check the air intake for any obstructions. I found the beginnings of some sort of rodent nest in the air filter housing a few years ago. When the tune-up was done, what brand of plugs and wires was used? These cars are partial to NGK and Denso.

[RIP]

Originally Posted by camry4ever

Appreciate the responses.
I forgot to mention earlier that CHECK ENGINE warning light has never come on when the engine is running. My understanding is that the CHECK ENGINE light will come on if ECM detects any anamoly. Therefore, I doubt if any diagnostic code can be retieved. Pls let me know if I am missing something here and should still run diagnostics.
The compression check was performed when engine was cold and compression built-up pretty quickly (within two or three compression strokes). One thing worth mentioning is that one of the spark plug tubes seal leaked which resulted in some oil seeping in around the spark plug. Subsequently, tube was resealed and spark plugs and wires were replaced. As I stated earlier, the vehicle has been very well maintained thoughout. Fuel pump pressure has not been checked yet and I was leaning towards replacing the fuel filter if that sounds logical.

Don't recall which but, some codes won't light the CE light. It only takes 5 minutes to check for codes. I'd bet you won't see any but, sure wouldn't hurt to make sure. I've read several times that 95/96 was a transition year for the change to OBDII fault system for Toyota. Some 95 Camrys fall into that. You might need a scanner.

Should perform a compression check on a warm engine. Seals expand, cracks (oh no!) rear their ugly heads, etc. Quickly rising pressures are a good sign.

Fuel filter? I'd check fuel pressure (under load) first.

What was the last maintenance done to the car prior to the problem and how long before the problem started?

Jennydee touched on it. Some experts recommend changing O2 sensors as scheduled maintenance. For your car they recommend changing them every 80K miles. I can't say I'm in that boat but, I do know they deteriorate slowly under normal use without setting a fault and can effect mileage and performance. In my mind your losses seems a bit beyond what a worn O2 sensor can do but, I am certainly no expert.

[Brian R.]

Your car most likely has an OBDI computer. V6 started conforming to OBDII in 1994. 4Cyl started OBDII in 1996. Your emissions sticker in your engine compartment will tell you which diagnostics are applicable. OBDI is just shorting the connector. OBDII needs a scanning tool.

[camry4ever]

I ran the diagnostics (by shortening TE1 & E1) but no codes were retrieved (check engine light keeps on blinking uniformly at regular intervals with no distinct pause). Also I did not see OBDII (or anything similar) on the emissions sticker in the engine compartment. Regarding plugs/wire brand, I always buy all the parts from Toyoto dealer.
I first noticed power loss around september last year but since I have another set of wheels, so did not bother too much about it :-) . If I remember correctly, the power loss occured almost overnight ( or a short period of time, 2-3 days) and no specific maintianence was performed around that time.

[Brian R.]

A possible source of your problem is the ECT sensor. Check its function versus the characteristics published in the service manual. I think a fuel filter is not likely to solve your problem, but you never know.

[davemac2]

Subtle drops in power like this are usually attributable to a clogged cat converter. I'm assuming here you may be more sensitive to the power loss than the average owner and are noticing the beginnings of the cat clogging. As an experiment, if it's possible on the 4cyl, unbolt the cat from the downpipe maybe briefly to see if it makes a big difference. Of course, all the other suggestions of fuel filter, blocked air intake, very dirty air filter, weak fuel pump can all be possible causes as well. Do the simple checks first such as air filter and air intake. For fuel, if you can get a hold of a fuel pressure gauge to stick on the fuel rail (ie attach to engine side of fuel filter inline), tape the gauge to your window and drive up that hill and see if the fuel pressure is holding ok.

dave mc

[camry4ever]

Mystery solved...

I was all set to take my vehicle to local Toyota dealer but the service rep. advised me to give Chevron Techron fuel additive a try. I added Chevron Techron Concentrate Plus Fuel System Cleaner to a full tank of Chevron gas and within few minutes of driving, the car felt like it just got off the assembly line!!! It got all the power back it was missing and some more... now running great and is extremely responsive. Moreover, the fuel economy also seems to be improved. Once I quantify the gas consumption improvement, I will post it to the thread. I am amazed at what wonders Techron is capable of doing. Note that I did try few other fuel additives from the local Walmart store over the last few months but to no avail. Certainly, Chevron's additive cleans more parts and much better than other additives.

I would like to thank all the folks for their valuable suggestions and I certainly learned alot from you all.

[RIP]

One of the few times I've read of an additive that actually worked. Always good to hear of an easy fix. Anxious to here the mpg news. Cheers

[jdmccright]

I've tried many brands...Gumout, Valvoline, STP...never have I seen such an improvement except for Seafoam. Treating an engine with it is more complicated (not just pouring it into the gas tank), but it certainly smoothed out a rough idle and throttle response. And it's not much more expensive than any of the others. But glad you found a good solution.

[Brian R.]

Originally Posted by camry4ever

Mystery solved...

I was all set to take my vehicle to local Toyota dealer but the service rep. advised me to give Chevron Techron fuel additive a try. I added Chevron Techron Concentrate Plus Fuel System Cleaner to a full tank of Chevron gas and within few minutes of driving, the car felt like it just got off the assembly line!!! It got all the power back it was missing and some more... now running great and is extremely responsive. Moreover, the fuel economy also seems to be improved. Once I quantify the gas consumption improvement, I will post it to the thread. I am amazed at what wonders Techron is capable of doing. Note that I did try few other fuel additives from the local Walmart store over the last few months but to no avail. Certainly, Chevron's additive cleans more parts and much better than other additives.

I would like to thank all the folks for their valuable suggestions and I certainly learned alot from you all.

I also have had good luck with Techron as an additive and used with Chevron gas. Probably other solvent would have worked also, but once I find one that works, why experiment unless it's really expensive?

[jdmccright]

I said I've tried many...but not all. Thanks Brian, I'll give the Techron a try when I don't have the time for Seafoam.