Intermittent driving issues

[micahd]

I am a Newbie. I have a 95 T-Bird SC that I bought from a "mechanic" this summer and have been seeing intermittent problems with the car. I suspect that I have a vacuum leak but because I'm not a mechanic, I wanted to get your opinions.

Issue 1: When starting the car while it's cold, the car runs pretty good and idles as it should. However, when starting the car after it's warm. It takes a while for it to start like it's not getting fuel. It often idles very rough and almost stalls.

Issue 2: My check engine light goes on and off throughout my driving. It's not a flashing or blinking light but it comes on from anywhere from 5 seconds to several minutes. It usually comes on when quickly accelerating and then letting off (passing) but does often come on during normal driving in the city. This may be a bit overboard but it seems like the light never comes on when I have the cruise control on. Once the light comes on during normal driving, I can turn on the cruise control and the light will go out. Could this be an issue with my chip?

Issue 3: I am almost always getting 18 mpg whether all highway driving or during city driving. I got 21-25 when I bought the car.

Issue 4: The car also has problems shifting in and out of gear, especially at slower speeds. Sometimes, when I quickly accelerate, it slips out of gear and then won't shift back unless I let off the gas pedal a few seconds.

Can a vacuum leak cause all of these or is it likely to be several issues at once?

I know this is rather long and I would have broken them into individual threads but didn't know if they were all related.

Thanks for any help!

[micahd]

Also, I did try to pull the codes for the engine light. However, I couldn't read anything because they aren't hard failures (so I'm told) and apparently, there isn't memory. At both Autozone and O'Reilly, I wasn't able to read anything from their scanners.

[KMT]

How many miles on the car?

How long since any kind of service or tune-up (filters & spark plugs?)

Do you know how to check the battery/voltage when off/starting/on?

Do you know how to check the various engine ground points & paths?

[micahd]

Originally Posted by KMT

How many miles on the car? 85,000 on car. Around 25,000 on new engine from Jasper.

How long since any kind of service or tune-up (filters & spark plugs?) Both around May 2008

Do you know how to check the battery/voltage when off/starting/on? Yep. I just changed the alternator the first week in September. Battery was checked then. Light was coming on before then.

Do you know how to check the various engine ground points & paths? Very little. I don't know where all of them are and what I need.

I don't know how to break up the quotes yet but will learn. I answered the questions within the quote above. Oops

Most of the repairs and engine replacement were done by the guy I bought the car from. He's a mechanic and his co-workers helped him when needed. Of corse, now that he no longer has the car, he'll charge for anything he does to it.

[DrFishbone]

Originally Posted by micahd

Issue 1: When starting the car while it's cold, the car runs pretty good and idles as it should. However, when starting the car after it's warm. It takes a while for it to start like it's not getting fuel. It often idles very rough and almost stalls.

All of my SC's do this - some worse than others, except I wonder if it's a problem with the starter being warm/hot. Another thought...I know when a regular distributor is well advanced, it has hard starts...could it be ignition timing?

[KMT]

>I just changed the alternator the first week in September. Battery was checked then.

Did you use a battery charger to make sure the battery was up, or did you simply put things together and let the alternator do the job?

As far as grounds go, you can start checking and then use what you find to decide how to continue. There is a ground strap that goes from the passenger side motor mount, forward and over to the body.
See the center of this photo...


If the connection is corroded/green, you should take action, such as replacement of the strap, addition of another, or at least remove the bolt and wire brush the ring tab & mounting surface - this is only a temporary fix, as the strap itself may be corroded over its length.

Finally, be sure the connections are clean and solid at the battery and the rear of the alternator. Replace any cables that are old...don't use cable clamps that attach to the end of the cable - find molded cables and clamps.

Check the ground path from the DIS to the battery by installing a temporary lead from the front/driver side DIS bolt directly to the negative battery terminal. If this improves how the car runs, consider removal of the A/C compressor bracket from the engine to clean paint etc. from where it mates to the block. Consider having the starter system checked for high amp draw.

If none of this helps, you might want to try to have the codes read again. If the check engine light is lit at times, there is a chance that stored codes are present. If you feel up to it, here is a link about reading the codes yourself with a volt meter...

I'm guessing the drop in mpg might be related to the trans slipping/acting up...maybe loss of OD. When was it last checked/serviced?

[pearl95sc]

CE lamp codes that come and go are hard to find, mainly because they are intermittent/self correcting problems, as so tagged by the ECM. If the lamp comes on, and is on solid, get the codes read immediatley. I got a rich code that I get, but it doesn't always pop up. In all honestly, sounds like you are running rich if you are getting less mpg and having issues with hard starting. Pull a plug and check to see if it looks fouled. Without other info, its hard to diagnose just what you're describing. Possible bad fuel pump, but that would depend on mileage and if the car is driven regularly with a low amount of gas. Most pumps last 10 years on average.

As far as the ground strap goes, the battery cable goes directly to the engine, and the small one goes to the core support. If both are in good shape, and the strap is still in one peice, rule that out. A bad ground won't cause bad mpg and hard starting, just a non starting and dead battery like symptoms.

Also, i'm guessing the shifting is with an auto. Check the MLPS sensor on the transmission. Been down that road before, and that stupid sensor can cause all sorts of goofy issues.

[micahd]

Originally Posted by pearl95sc

CE lamp codes that come and go are hard to find, mainly because they are intermittent/self correcting problems, as so tagged by the ECM. If the lamp comes on, and is on solid, get the codes read immediatley. I got a rich code that I get, but it doesn't always pop up. In all honestly, sounds like you are running rich if you are getting less mpg and having issues with hard starting. Pull a plug and check to see if it looks fouled. Without other info, its hard to diagnose just what you're describing. Possible bad fuel pump, but that would depend on mileage and if the car is driven regularly with a low amount of gas. Most pumps last 10 years on average.

Good info. I doubt the pump has ever been changed.

Originally Posted by pearl95sc

As far as the ground strap goes, the battery cable goes directly to the engine, and the small one goes to the core support. If both are in good shape, and the strap is still in one peice, rule that out. A bad ground won't cause bad mpg and hard starting, just a non starting and dead battery like symptoms.

That's kind of what I figured but didn't know for sure. It looked fine anyway.

Originally Posted by pearl95sc

Also, i'm guessing the shifting is with an auto. Check the MLPS sensor on the transmission. Been down that road before, and that stupid sensor can cause all sorts of goofy issues.

Yes, you're correct. It is an automatic. What's the best way to check this sensor? Neither of my repair manuals show this, unless I'm just blind. I still haven't received the factory repair manual so I only have Haynes and Chilton right now. Soon, hopefully!

[micahd]

Originally Posted by DrFishbone

All of my SC's do this - some worse than others, except I wonder if it's a problem with the starter being warm/hot. Another thought...I know when a regular distributor is well advanced, it has hard starts...could it be ignition timing?

Not sure but it does make sense. Wouldn't that make it consistent though?

[pearl95sc]

The mlps is the sensor on the shifter of the transmission. Kinda of a non testable part. Might be a way, but i'd just change it. It can cause random downshifts, and erratic shifting. It's a 38$ part, or it was something like that when I replaced mine on my 94. Mine didn't need it, but it was a good peice of mind.

You could grab a multimeter and check the resistance across the 2 prongs of the sensors, temp, iat. make sure the values correspond correctly. if the sensors are shot and putting out a constant code, the computer could be putting out additional, or less timing, all the time, and not accounting for the change that is actual. all while the o2 sensors are seeing strange results, thus filppin on the CE lamp.

OBDI problems suck. Always a pain to diagnose.

[mannysc]

firts off where do you live?

now maybe a local can help out .

my guess is bad connection try cam sensor check oxy sensors connections also check this out I had a 92 sc that had zero fuel pressure when cranking fuel pressure reg was bad it would work then not work id hve to crank for long time to start .

if i turned on key waited 15 seconds turned it on again waited 15 seconds then cranked it fired up fast I had ti prime fuel system to get it to fire up .

i replaced the pressure reg at back of fuel rail and it started up like a new car from then on maybe problem maybe not . just shooting some info your way

[micahd]

Originally Posted by pearl95sc

The mlps is the sensor on the shifter of the transmission. Kinda of a non testable part. Might be a way, but i'd just change it. It can cause random downshifts, and erratic shifting. It's a 38$ part, or it was something like that when I replaced mine on my 94. Mine didn't need it, but it was a good peice of mind.

Thanks! That's worth the price so I'll just change it. Sleeting today so that kinda stinks.

Originally Posted by pearl95sc

OBDI problems suck. Always a pain to diagnose.

I'm finding that to be so true!

[micahd]

Originally Posted by mannysc

firts off where do you live?
now maybe a local can help out .

I'm in the Kansas City area. I've been trying to watch for one but maybe I'm looking in the wrong places.

Originally Posted by mannysc

my guess is bad connection try cam sensor check oxy sensors connections also check this out I had a 92 sc that had zero fuel pressure when cranking fuel pressure reg was bad it would work then not work id hve to crank for long time to start .

Thanks. I'll keep that in mind.

Originally Posted by mannysc

i replaced the pressure reg at back of fuel rail and it started up like a new car from then on maybe problem maybe not . just shooting some info your way

Hey, I appreciate any help I can get. Maybe someday, I can return the favor to those that helped me.

[Young-SC-Owner]

Micah, go here....


http://www.sccoa.com/forums/forumdisplay.php?f=57


Plenty of MO boys

[micahd]

Originally Posted by Young-SC-Owner

Micah, go here....


http://www.sccoa.com/forums/forumdisplay.php?f=57


Plenty of MO boys

Thanks for the link! And congrats on the wedding!