Contour Enthusiasts Group Archives Forums General Troubleshooting Dirty fuel injectors?

I have a '95 Contour, 4 cyl., 5 speed.

It had been occassionally kind of hiccupping or hesitating a little when accelerating...thought maybe it was fuel injectors.

I tried some fuel injector cleaner...a couple of cheap ones, since problem was pretty minor. One day last week it was doing its usual occasional minor hiccuping on the way to work, but after work when I started up, it was immediatly really bad. It is like there is no power and acceleration is kind of jerky...like the hiccups but continuous. Kind of sounds like a sewing machine when accelerating, but runs smooth when idling.

This weekend I put another fuel injector cleaner (brand was Gunk...concentrated...) in on Saturday and today it seems like it was perhaps occassionally getting a little better...but not sure yet.

Am I on the right track in thinking fuel injectors are the problem? Has anyone had success using any particular brand of injector cleaner? The most recent stuff I put in (Gunk) says to use every 6000 miles...some others say you can use every tank...are there any problems caused by using too much injector cleaner or using it too often?

With a search, I had found some previous posts here about fuel injector cleaners. Several recomended replacing fuel filter after using the injector cleaner...does the cleaner cause the filter to get plugged up? Also some said to "drive it hard" with the injector cleaner in the tank...does that mean heavy acceleration (so I should drive like I normally do :-))?

Formula 1 synthetic fule injector (concentrated) :p

Anyone know about the NOS Fuel Injection Cleaner?
I tried this out last week just as a precaution.
No real problems before or after that is...

If it's hiccupping, have you checked the plugs and wires lately? Maybe the "hiccups" are really misfires. My '98 Contour needed plugs/wires at 35K miles while my '97 Mystique just keeps smoothly firing with the originals as it approaches 60K miles. Go figure!

If you put injector cleaner in the tank, I suggest taking it on a long expressway drive so the engine gets hot and the gas with the cleaner in it is running thru the engine at a continuous high rate for a period of time. Aggressive stop-and go driving really will not get the injectors as clean as a sustained high speed drive.

Finally, yes, change the fuel filter after using the cleaner. The cleaner tends to "scour" everything in the fuel system and will probably result in additional "junk" being taken out of the system in back of the filter and getting trapped in it as the fuel passes thru.

Good luck.

I thought about misfiring possibility, but since it runs perfectly smoothly at idle I did not think this was cause. I believe plugs were replaced by dealer I purchased it from about 9 mo./10K ago...not sure about wires, is any way to check the wires?

Current symtomes are: When let clutch out to get going it starts running crappy and power is much less than used to be also have now started hearing a couple of pops that seem to be coming from exhaust system right as I start moving never at any other time...like real mild backfiring. Seems to run better at high rpm and also now seems pretty smooth at steady speeds as long as rpm is a bit higher than I normally would run it at.

I have not looked for the fuel filter yet, is that pretty easy to get to? I am going to try at least one more tank of gas with injector cleaner before I do anything else as seems to have improved some with latest dose. I have not seen the formula 1 stuff that was suggested, so I am giving Chevron a try this time.

Is it possible initial dose of fuel injector cleaner caused original problem to get worse by loosening up junk elsewher in the fuel system and depositing it at the injectors?

It is possible that the injector cleaner loosened up some stuff and it is causing the engine to run even worse.

But IMHO, fuel injector cleaner is crap. It will probably just clean out your fuel filter more than your injectors. Redline Fuel Injector Cleaner is the only one I can say works. The true way to clean them is to simply pull the injectors out and blast the cleaner through it (professionals only).

Lance put together a nice how-to on replacing that stuff. Try it.

One last thing -- the throttle body and intake manifold might be dirty. That caused some poor throttle acceleration on mine.

Your car is old enough and probably high mileage enough that Idou2's suggestion of plug wires is a strong possibility. Also could be a problem with your timing advance. Suggest you visit a shop that you trust. If it's just plug wires, that's a cheap fix.

Well, I know whats wrong with your car! My 95 gl zetec started doing the exact same thing the other day.....took it to the dealership this morning.......maf failure....was about 290 to fix at dealership, but cheaper if ya do it yourself!

What is maf?

i believe its the mass air filter. anyone want to 2nd this or correct me?