Any car mechanics out there?

“I know this is a backpacking forum, but I was hoping that maybe someone on this forum might be able to help. I also put this up on a Subaru Forum.

I’m having a problem with my 1998 Forester. My check engine light keeps coming on and is accompanied by a rough idle when the car is stopped. At RPMs over 3000 it runs fine. The problem started in the fall and was the result of cylinder misfires, which resulted in the replacement of all the spark plugs, plug wires, and coil pack. The car ran fine all winter after that. Now I am once again having the same problem ever since the weather warmed and became more humid. I brought the car in for servicing and was told that the cylinders were misfiring and I should have the plugs and wires replaced. I shouldn’t have to replace them every 6 to 8 months. Any ideas as to what may be the rout of this problem?”

“I wish I knew. My first Wrangler did the same thing. I swapped out the plugs and wires and it helped for a few months, but the problem came back just as yours has. I wound up trading it in when I couldn't figure out the problem.

I'll email a friend who's far better with cars than I am and see if he knows.”

“Have you checked the alternator?

A bad alternator can start showing itself in all different forms of electrical gremlins.”

“Well it could be many things.. Have you had it put on a scanner yet?.. have you got any codes from the computer?. It could be anything from an O2 sensor to Map sensor, Idle control sensor, cloged up cat converter. have you changed the fuel filter yet, it could be cloged on an idle and than when you up the rpms you could get fuel then?.. Believe it or not you could have to change the air filter as well. You could also have a vacume leak?.. actuall without seeing the car.. its pot luck.”

“One of my boys here said that it could have also jumped timming.
Does the light stay on all the time. Or goes off when the engine is warm?”

“I am amazed at how often a faulty oxygen sensor can cause various engine problems. That may be your problem.

Also, have you had the dealer hook it up to the engine diagnostic computer for analysis? Too many dealers just want to guess and charge you for parts. Have it diagnosed by computer and see what that says. I have a 1999 CHrysler with 30,000 miles and do not expectto change spark plugs in the furst 100,000.”

“Spark plugs really shouldn't be going bad nowadays, My '96 Blazer has 160,000 miles and the same spark plugs it started with, they fire like brand new.”

“Wow 3 hits already on this site and none on the Subaru site.

Mouse – They did run a computer scan on the car at the shop and all that came up was misfires in 3 of the 4 cylinders. I did just change the air filter last week thinking that could have something to do with the problem, but now luck; it need to be changed anyway.”

“that should be 6 hits”

“okay let me do a bit of research..
what size motor is it and how many miles?”

“Whats on the O.D.?

Timing belt? Faulty computer,sensor problem? Mixture problem?”

“My friend responded to my email. He's been right many times on my cars and spends his free time modifying his collection. Now that I think back, his suggestion to use cleaner worked as a temporary fix on the first Wrangler, too.


"I am not sure on those cars, but I had a similar problem with mine. Have him check the IAC (idle air control). When they get carbon buld up they function all crazy. The reason there are no problems after 3000 RPM is
because then no air is passing through the IAC, just the throttle body.
You can take them off and use carb cleaner on it, then use a little WD-40 to lube the inside of it. This is an OK fix. I cleaned mine a few times
and had to just replace it after a while."”

“okay without all the info> If you have a twin cam.. cylinders 3&4 are on one side and cylinders 1&2 are on the other side.. okay now what that means is that if you have a misfire on 3&4 they are on the same side.. now.. You may have jumped a tooth on your cam (timing belt) which will run good at a high rpm but will rough idle at idle. Have you changed your timing belt on a regular schedule?.
they sould be changed 100,000 or before.”

“Motor size: 2.5L (Flat 4)
Mileage: about 113K

Also I had the fuel system cleaned when I had it serviced the other day.”

“I bought the car at 80K and I haven't changed the timing belt on it, so I'm assuming it hasn't been changed.”

“okay, and idle air control sensor will not misfire just cylinders 3&4..According to my books there are two 2.5L listed.. can you check your vin number and check the sixth diget and see what it is.?”

“Some vehicles have to have the timing belts changed at varoious milieages. some are 30,000 and some are 60,000 and so on.. you should check with your mechanic to see exactly what is recomended.. however yours is 100,000.. never assume that it was done.. it can be a costly repair, and sometimes if you have what they call an interferance motor,, when you throw your belt you will destroy your motor.”

“I'll have to check the VIN later when I get back to my car. If it helps the car was one of the early '98 models. I know they made some changes to the motor on models made later on that production year.

BTW - I'm not exactly sure which cylinders were misfiring, I was told 3 of the 4 were misfiring but I don't know off hand with ones. I think it was 1, 2, & 4, but I'm not positive. I think it says on my bill.”

“I will also check my paper work on the car from when I got it. When I bought it I received a list of all the work that was done on it.”

“let me know later about the vin code.. Ive got to get back to work.. ive got at least 5 cars waiting on emissions..”

“Thanks for checking things out for me.”

“no problem. This is what i do for a living..”

“"okay, and idle air control sensor will not misfire just cylinders 3&4..According to my books there are two 2.5L listed.. can you check your vin number and check the sixth diget and see what it is.?"
mouse
09:51:13 AM
07/15/04
ignore this user

Sixth diget is 6.

Let me know if you need the entire VIN. I'm not completely comfortable listing the entire thing on a public forum.”

“lumberzac.
I appriciate the fact that you are leary about posting your entire vin number. The good thing is that i do not need it.. just the sixth number or diget. Let me do some more reasearch and get back to you.
Can you tell me for sure what cylinders were listed as a misfire?”

“I checked the bill and unfortunately it doesn't say which 3 were misfiring.”

“The car generally only acts up when it’s hot and humid out. It will run like crap for a few days and then run fine again.”

“im sorry to say that we believe that it is your timing belt for sure. keep in mind that we have not looked at it, just from what you have said. You really need to get that timming belt changed. If you have any records of the vehicle maintance records go thru them. If i were you i would call your garage up and get some prices on the repair, and than go from there. good luck..ps. your motor is an interfearence motor so if your belt breaks you will destroy your motor. And you really dont want to replace that. I wish you luck.”

“Thanks for the help.”

“lz, if the timing belt in that car has never been changed, or you don't know if it has, then definitely, you really, really need to change it. For sure.

I had one break in my Chevette once. Well, twice actually, but once was while it was in the shop. Anyway, fortunately for me, the Chevette engine was non-interference, so all I needed was a new timing belt. But seriously, your car should be in the shop now having that thing replaced if you don't know when it was last done.”

“thanks for the adivce for lumberzac, Sometimes people dont like to take advice from a woman. However you are correct. It is very important to have regular maintance done.. not just oil changes. The bad thing is that most people dont know about them. If you have a good mechanic they should have advised you. I see it all the time.”

“I just thought I would add an extra voice, mouse, it didn't have anything to do with your being female. Plus I am OCD so I am worried, right now, about lz's car, lol...”

“Thanks for the advice everyone. I still haven't gotten a reply from the car site. I had the feeling that this was deeper than just plugs and wires considering they were replaced less than a year ago. I defiantly wasn’t going to spend over $200 for something I already did for about $40.

How involved is changing the timing belt? All my previous vehicles had timing chains, which is a real pain in the ass to change. If it isn’t something I can do I will try and make an appointment sometime next week.”

“It depends on the engine, lz. mouse will have a better answer than me.”

“Thinking about it, I probably should have someone else do it. I needed to use 2 jointed sections on my ratchet just to change the spark plugs.”

“Did you change the timing chains yourself?”

“"Did you change the timing chains yourself?"
bitpusher
10:52:29 AM
07/16/04
ignore this user

No, never had to.”

“OK, then I would say that it would be best to have it done by a pro. If you had changed a timing chain, then I'd think you could handle changing the belt no prob.”

“Changing the belt its self is easy. It's making sure everything lines up properly that is the hard part.”

“Well, sure. I've always had a pro do it because I don't have the patience to get the first piston at TDC, lol...”

“I wouldn't tackle a timing belt job even if I had all the right tools and a manual especially on a new car.

I had my T.belt changed sometime in the mid 90k range and while that was getting change out I had the water pump replaced because from what others have said in the past,, 'you might as well replace the pump while we are in there.' I look at that as a preventive measure for the future.

There was no extra labor charge for replacing the water pump since it was in the way of getting to the belt. I'm hoping to get another 40 to 50k and take this truck to the 200k marker.

Best of luck,,shop around for the best bid,, I betcha its a greasy 1200$+.”

“$1200? Wow. Never cost me more than $200 on either of mine, but they were both rear-wheel drive and so the timing belt was more easily accessible. (at the front of the engine compartment, not over a wheel well, dontcha know)”

“I hope you aren't right about the price BR, because there is no way I can afford that. I'm can barely make ends meet as it is.”

“Me too,,, but if I remember correctly that is close to what I paid,,,at the dealer of course. I just wanted it done right, so I took it to the dealer I bought the truck from and told them what I expected. Outside of tires and oil change/maintenance that belt/pump change out has been my greatest expense to date on the truck.”

“It costs a fortune to fix cars these days and to make matters worse each year they get more complicated and it limits what work you can do yourself.”

“"It costs a fortune to fix cars these days and to make matters worse each year they get more complicated and it limits what work you can do yourself."
RichB
11:49:20 AM
07/16/04
ignore this user

Some times I miss my old sh*tbox Ford. It would break down about once a week, but it was easy to fix.”

“I read that today's cars have around 11 computers on them, so it's no wonder that when something goes wrong you are really stuck on trying to fix it. The older vehicles were good in there own way, but I'm glad I got rid of the lemon 1988 Astro van I had. It had a parts appetite that was incredible and wasn't exactly cheap to fix either.”

“sorry i have not got the price quote for you yet.. its been swamped around here.. And yes i still have to check but getting the water pump at the same time is a real smart idea. Briar Rabbit is right, you will save on labor. And the pumps are not as bad price wise as they were years ago. Same goes for rotors, they are much cheaper than they use to be, but they are junk metal you can no longer cut them down. I cannot remember ever charging quite that much for the belt, pump and labor. But Im in penna. maybe our labor rates are not as high. I will get back to you as soon as i can.”

“I got an estimate today for the timing belt and water pump. $355 plus tax and coolant. It’s going to hurt paying that at once, but it’s a lot cheaper than paying for a new motor if I don’t get this done. The garage is going to take a look at the car before they do the work, just incase it is something else. Wouldn’t it be nice if our vehicles never had parts that wore out?”

“That's not too bad. Cheaper than a new engine, for sure.”

“I figured that wasn't too bad considering it was going to cost me over $100 for the parts to do it myself.”