skip and loss of power please help

[hondakiller44]

My 93 GT has a nasty skip and loss of power when it is under a load. It happens when I get on it hard, when i try to give it gas under 2k, and sometimes up hill. I have been racking my brain for months now trying to fix this. So far I have tried the following:

New cap and rotor, new msd wires, new bosh platinum plugs, msd coil
checked the map and mas sensors and they are good.
retarded my timing back to stock(10) thinking it may have been to advanced
changed the fuel filter
upgraded to premium fuel
eliminated my high flow cats thinking they may have been plugged

The only mods i have on the car are cold air intake, msd 6al ignition, shorty heads, x-pipe and 3 chamber flow masters.

I just got a vacuum diagram so i will check for vacuum leaks or clogs.

Anyone have a similar problem and find the solution?

What do you guys think it could be?

 

[331 stang91]

Probably not it but check the tps censor may need a new one or change voltage. I've heard of those really screwing things up. But its a long shoot and I don't really think it matches all you problems but easy to check. Good luck!!!

 

[Curse]

Probably not it but check the tps censor may need a new one or change voltage. I've heard of those really screwing things up. But its a long shoot and I don't really think it matches all you problems but easy to check. Good luck!!!

a bad TPS sensor could cause this. My TPS was bad and would not show up on the code reader. Another thing I would do if I were you would be to get rid of those crappy bosch platinum plugs. MSD does not recommend them when using one of their boxes. Stick to autolites non platinum, good luck.

 

[my$100project]

:OT:

: Stick to autolites non platinum, good luck.

Didn't realize there was any disanvantages to platinum tip plugs? The way I understood it they corroded less, thus extending the life of the plug? Am I wrong here?

 

[Curse]

:OT:

Didn't realize there was any disanvantages to platinum tip plugs? The way I understood it they corroded less, thus extending the life of the plug? Am I wrong here?

The MSD will burn the platinum right off the plug, getting the plug so hot that you will create hot spots in the combustion chamber ultimately causing a misfire and detonation.

 

[my$100project]

ahhhhhhhhhhh, thank you--thank you

 

[Curse]

No prob always happy to help out.

 

[hondakiller44]

hey curse did your car have the same symptoms? Do you know if the missfire from bad plugs would be under heavy loads or all the time? I will check the tps and see what happens.

thanks alot for the help guys much appreciated

 

[Curse]

hey curse did your car have the same symptoms? Do you know if the missfire from bad plugs would be under heavy loads or all the time? I will check the tps and see what happens.

thanks alot for the help guys much appreciated

Kind of, my misfire would happen under 2000 rpm after 2k my car would start to feel ok but I would have a ton of detonation. My dad (an MSD Tech) then told me about platinum plugs with MSD boxes. Changed the plugs never had another problem. Are you having any detonation problems? If so then I suggest you put some new non platinum plugs. Good Luck

 

[hondakiller44]

yea i am having detonation which is causing the skip i think. If you could do me a favor and ask your dad if the platinum plugs are bad from the start or if it takes awhile. The reason i ask is i just put them in two weeks ago and i still had the skip right after. I would hate to take them out if its not the problem.

thanks

 

[jrichker]

Follow the list in the order it is given, you'll spend less time & money .

1.) Bypass the MSD box & temporarily put the ignition back to stock. You don't need an MSD unit unless you have NO2 or pressurized induction.

2.) Clock the MAF and see if the problem changes

3.) Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $33.

4.) Swap the TFI with a spare one if you can borrow one. TFI's are known for causing odd ignition problems.

5.) Check the fuel pressure under load. This may require you to spend a few $ to buy or rent a fuel pressure test gauge. You can stick it under the windshield wiper and make some test runs.

 

[hondakiller44]

sounds like a good list to follow. I already swapped out and ran with out the MAF and that didnt help. I also put the car back to stock ignition and the problem was still there. So i guess i will be checkin the codes next. How do you remove the TFI module?

thanks

 

[Curse]

yea i am having detonation which is causing the skip i think. If you could do me a favor and ask your dad if the platinum plugs are bad from the start or if it takes awhile. The reason i ask is i just put them in two weeks ago and i still had the skip right after. I would hate to take them out if its not the problem.

thanks

You had the problem before you put the platinum plugs in? If it is the platinum plugs, it would did almost right away. If you plan on keeping you MSD box, then i say you switch the platinum plugs out anyway. Good Luck

 

[hondakiller44]

actually the problems started after i installed an msd coil and ignition. I have since swapped back the original coil and ignition and the problem is still there. I had platinum plugs prior to the msd installs with no problems. would the plugs be bad all the time because of the msd? would there still be detonation if the msd was not connected? because i still have detonation without the msd installed.

 

[Curse]

Have you pulled a plug out yet? I would pull a plug and check to see if there are any heat blisters on the porcelain part of the plug. Have you checked your timing?

 

[hondakiller44]

The plugs i have in there now are only 2 weeks old. I went from a bosch 2 prong to single. the 2 prongs were not blistered and they were used with the msd. I had my base timing set at 13 so i tried retarding it back to the original 10 but the skip was still there. I will check a few of the plugs i have in there now to make sure they are not blistered.

 

[hondakiller44]

Oh yea fixed the problem. It was a bad TPS. Replaced all those parts and it turns out it was right in front of my face lol. Thanks for the advice Curse saved my ass. You ever need any help or anything let me know i will do my best.

thanks again guys

 

[331 stang91]

I run I think tripple platium plugs in my truck and a msd 6a and have not had problems?

 

[331 stang91]

how long would it take for the platium plug to have problems from the msd?

 

[my$100project]

The plugs i have in there now are only 2 weeks old. I went from a bosch 2 prong to single. the 2 prongs were not blistered and they were used with the msd.

ok Here I go changing the subject again. Is there any advantages to two prong plugs? The way I understand it is the spark archs across the parh of least resistance. Seeing as how there would be two prongs it would just fire on one every other arch. (colder of the two). Wouldn't using a one prong and positioning the open end of the plug towards the fuel injection side of the cylinder be more efficient and give more performance than a "two or 4 prong" plug?