JBster

So i took my girl out for a spin today and it was obvious she was hurting. That was 2 weeks ago....

I recently had a misfire in the 5th cylinder (check engine light read), and when I took out the spark plug it looked like it was running very lean (tannish color on the plug tip). I put some dry gas in the tank because it seemed like it might have been water in my tank. All was good for about a week, but then it went down hill from there.

My Gt seemed to "cough" as I was driving down my street, and there was a significant loss of power. This cough seems to also cause a shake at idle. But after a short drive and turning the car off at a pizza place, the car would run better than normal - much better/faster than before the problem even started. I really have no idea what it could be, seems like fuel injectors, but I am not sure. Also, it tends to happen when it is wet out, but not all the time. Any one have any clue? Should I put money into a new sparks, coils, and injectors at 64,000 miles?

Last week was obviously my lucky week, because my heater core also went. It left a wonderful antifreeze smell in my car. But now that that is fixed (by the way it takes forever to swap it out they should put the core in a better spot), I need to focus on the real problem. Any ideas at all?

Thanks

WhiteFoxGT

Figure out which cylinder is misfiring.. Which is hard to do without a datalogger scan tool. A IDS/WDS would be optimal.. Know any Ford techs? Its most likely a faulty coil. I hate tryin to diag "random" misfires over the net. But from experience with problems like that, you find the cylinder thats doing it, and replace the coil/plug, and problem solved.

JBster

yea I checked it on the scanner and it said the cylinder 5 was misfiring, but that was a long time ago. It hasn't gotten a check engine light in 2 weeks after the dry gas, and the logger shows that the 5th cylinder is around the same range as the other 7. Could it still be a misfire even though the computer isn't picking it up? Also, is it ok to replace just one fuel injector? Some1 told me to replace all of them at once or else one may be over powered - sounds like a line to me, but I don't know.

thanks for your help.

WhiteFoxGT

You can replace one injector at a time, but I wouldnt jump to conclusions. Like I said, if it looks like #5 is off compared to the others, I'd swap the coil with on from the other side (#1 for example) to see if the misfire follows.

JBster

ok will do and post findings.
Thanx

WhiteFoxGT

Oh and is the car a 5spd or Auto? If auto, put it in drive with the powerbalance up and power brake it a bit, and see if you can get it to misfire under load. If its a 5spd, carefully drive it around, put it in 4th at low speed and roll into it. Try to get it to show the cylinder misfiring...which is usually worse under load. Its usually hard to find a mis just by idling or revving out of gear, unless its a DEAD miss.

JBster

Yea i have tried that as I figured it would get it to misfire, but the computer shows no check engine light and about equal firing rates for all eight cylinders. Can't figure if it is a misfire. Any idea if something else could be causing the performance? It just seems wierd that it would have a crappy ride, and then ten minutes later be much faster and smoother than normal. Confusing.

I've heard about a weather switch that causes the engine to perform differently. Think that could cause something like this (if that even exists)?

jojo2003

Does it do it when it is around 1500 RPMs. Mine does the same thing, but I have it narrowed down to going about 60 in 4th, and then shift to 5th, and the rpms will go down to around 1500 rpms, and when I give it gas it does that. But once I get going, or past that, it will stop, until I dropped down RPMs again. Does that sound like yours?

JBster

it seems to do it from 500 - 1500 rpms then it goes away no matter what the gear is. It also seems to go away with time, so it won't do it after about 15 minutes of driving, after I turn it on and off. Really wierd...

JBster

Fuel injectors and sparks have been replaced and the cough is still there

What happens when the fuel pump is going? could it be that?

Any other ideas?