Problems when engine is hot

I'm having a problem with the car hesitating when it's hot. Now that the weather in Ohio is close to 90. Just the last few days, when I drive for a long way (30+ miles) or when I've been sitting in traffic it starts hesitating at WOT. Seems OK till I get around 3K rpms.

I suspect the CAI might be getting too hot, so I put my stock air box back on and reset the computer. I'll be taking it to the dealer soon anyway, so I'll have them look at it then if it's still happening.

Anyone see this before?

Not overheating, according to the temp gauge. Cleaned the MAF a couple of months ago. Had a similar problem then after I cleaned the K&N filter (too much oil).

BTW. I only run BP or Shell gas. 87 octane. Are you suggesting a higher octane or just avoiding gas from the convenient stores?

Kilgore Trout said:

Probably got oil build up on it again, the curse of the K&N

I am really starting to think that Motorcraft paper > K&N...

Click to expand...

Cleaned my MAF today. Seems like that fixed it! Went for a drive that was about 35 miles and no problem. Probably won't know for sure until I drive it more.

I'm keeping the stock airbox on for now.

I wonder if hot weather causes more oil to pass from the K&N into the intake system. That's the only thing I can think of that would explain this.

Mr GT 02 said:

how do u clean the MAF sensor??? and with what???
I think i need to do the same thing.....

Click to expand...

Here's the text from an article on the subject...

Cleaning The MAF Sensor
Do you own a 1994-2000 Mustang GT? Have you experienced pinging or detonation at WOT? Well then, this might just
be the fix for you! It seems that many of us that have installed a K&N filter just might have caused the MAF (Mass Air
Flow) Sensor to become dirty. K&N filters are pre-oiled and some of this oil will find its way onto the sensor causing the
sensor to malfunction and in turn cause your engine to run lean at WOT.

Submitted By: TxFrog1999
Cleaning The MAF Sensor

Now just a quick clarification, this is not the only cause for pinging, and if you own a 2001, it might be your high
compression ratio that is causing the detonation. Ford seems to think that 87 Octane is fine for our cars, in fact on pg.
188 of the 2001 owners manual (some manuals will differ) Ford states:

"Your vehicle is designed to use "Regular" unleaded gasoline with pump (R+M)/2 octane rating of 87. We do not
recommend the use of gasoline labeled as "Regular" that are sold with octane ratings of 86 or lower in high altitude
areas. Do not be concerned if your engine sometimes knocks lightly. However, if it knocks heavily under most driving
conditions while you are using fuel with the recommended octane, see your dealer or a qualified service technician to
prevent any engine damage."

Owners Guide, Mustang (2001 Model Year); Copyright 2000 Ford Motor Company

Now does anyone else find it odd that Ford says its ok for our engines to "knock lightly"? Well I did, and I took my 2000
GT to my dealer for a fix, and according to them Ford has informed all dealers that if any Mustang owner complains
about knocking that they should instruct them to run 93 Octane gas or detune the engine. Now since I wasn't informed of
the possibility that this car would require a high-grade gasoline to run normally and since I won't accept a retune and loss
of performance others and myself decided to find a solution on our own.

WARNING
I am not responsible for mistakes made due to ignorance, lack of patience, or simply following my directions as though
God wrote them.
So before we begin I'm sure many of you have one question on your minds: "Does this work?" Well yes and no. Clear?
Ok, as far as I can tell cleaning the MAF is just as important as changing your oil, and in some cases can stop the light
knocking at WOT. I cleaned my MAF Sensor and it fixed my pinging, but more severe cases of detonation may require a
trip to the dealer as stated in the owner’s manual.

Tools and items needed to complete the cleaning:



-

T-20 Torx Bit (Tamper Proof)

-

Electrical Contact Cleaner Quick-Dry Only (Can be found at AutoZone for around $2)

Note: The MAF Sensor is VERY delicate, so be sure to remove it carefully and never touch the sensor directly!
This is the MAF Sensor:



First, disconnect the sensor from the electrical harness:



Next, use the T-20 Torx bit to remove the two bolts connecting the MAF sensor to the air box:





Now remove the MAF Sensor, and remember to be careful because the sensor is delicate!



Here is the sensor, use the contact cleaner and spray a generous amount on the sensor. Allow the vapors and cleaner to
evaporate fully.



Now reinstall the sensor, make sure to reattach the harness and take her for a test drive.
http://www.stangnet.com - Ford Mustang | StangNet.com Powered by Mambo Generated: 10 April, 2005, 19:21

Mr GT 02 said:

ok...what electric cleaner did u use? Cause I went to autozone and I explained to them that I need a cleaner that cleans the MAF sensor. the employee seemed uncertain of what i was talking about but he then gave me a can of CRC LECRTRA-MOTIVE Electric Parts Cleaner. I read the back of the can and it says that it cleans and degreases, Electic Motors, starters, electric cables, solenoids, Altenators, Coils, ETC....

Is this the cleaner I am looking for? I did a test spray in the air and the spray comes out fast...........that wont damage the little sensors???? Oh and it says to avoid overspray on plastic parts....but i see that the sensor is surrounded by plastic......


Any thoughts? or should I just spray the darn sensors with teh stuff...lol

Click to expand...

I bought cleaner at Advance Auto Parts. It's made by CRC. It's called "QD Electronic Cleaner, Quick Drying Formula".

I have run a few days now with the stock airbox. Thought this problem was fixed.
Again, problem was some hesitation above 3K rpms.

Then, today I had to drive about 65 miles and it started happening again. Not as bad as before, though. Outside temp was about 85 degrees.

I was low on gas, so I decided to try running a higher octane. So, I stopped at Shell and filled up with 93 octane. I was at less than 1/4 tank. The rest of the way home (about 10 miles), it seemed alot better.

Now I'm really confused.

Just thought I'd post this since others seem to have this problem too.

Well, here is my update.

First thing I did was change my plugs and one of the COPs that recorded a misfire on my Predator. Improved the way the car runs, but did not fix the problem.

Next, replaced MAF with OEM part. Seemed to help alot, but did not fix the problem totally. Also went back to using CAI, since stock airbox did not fix it.

Last weekend, replaced the TPS (throttle position sensor) and now I'm waiting to see if it's fixed. Won't know until I do some more long distance driving. However, results so far are encouraging. I have been using my Predator to do alot of data logging. I had been seeing alot of misfires recorded with weird TPS voltage readings. Since I replaced it, haven't seen this.

Saving alot on labor, but I think I'm over-budget on parts.

Replaced fuel filter @ 30K, which was about 6 months ago.