Mustang 5.0 is surging

Mustang 5.0 is surging
ill try to make this as short and precise as possible i changed plugs, wires, cap, rotor on saturday 4-21-07. car ran great up until wednesday morning. (i used all good stuff. double platinum plugs, FMS wires, MSD cap and rotor.) wednesday morning i was going to work and the car idle was jumpy.....and at anything below full throttle you can feel and hear it surging. i have since replaced the fuel filter and added some good FI cleaner. still nothing. i have triple checked all plugs and wires. everything is good and tight. i have no CEL on so i didnt think it was a sensor, but now after driving it today it may be the TPS. im also thinking it maybe the fuel pressure regulator. i had originally thought feul pump but everyone i talk to say those things either work or they dont....no in between.

Check fuel pressure. Check for vacuum leaks. Clean the MAF element with electrical contact cleaner (use it only!!!!) and check its voltage if you can. Clean IAC and throttle body. Check TPS voltage (use an analog gauge and check the "sweep" to look for any jumpiness that will indicate a faulty TPS). Get back to us. Hope this helps. BTW, how old are those O2 sensors? Just checking. Most people never change them until they are bad, but every 50K miles should be the max for them. I doubt they are your problem though (usually not related to what you are describing), but I just wanted to check.

Check fuel pressure. Clean the MAF element with electrical contact cleaner (use it only!!!!). Clean IAC and throttle body. Check TPS voltage (use an analog gauge and check the "sweep" to look for any jumpiness that will indicate a faulty TPS). Get back to us. Hope this helps. BTW, how old are those O2 sensors? Just checking. Most people never change them until they are bad, but every 50K miles should be the max for them. I doubt they are your problem though (usually not related to what you are describing), but I just wanted to check. im going to test fuel pressure by tomorrow, and hopefully get a volt meter to check the TPS. hadnt thought about cleaning iac and maf. im unsure how old the O2's are. the car has an o/r pipe so i believe the rears have the MIL's on them. unless fox's are weird. lol but again wouldnt the o2's and even the tps and things cause a CEL. i know the CEL works as it comes on during start-up then goes off.

I'd put some cheap coppers back in it.

I'd put some cheap coppers back in it. but it ran fine when i did them for the first 4 days. and i actually removed platinum + 4.s dont know why anyone put those into a baisically stock 5.0 to begin with.

Check fuel pressure. Clean the MAF element with electrical contact cleaner (use it only!!!!). Clean IAC and throttle body. Check TPS voltage (use an analog gauge and check the "sweep" to look for any jumpiness that will indicate a faulty TPS). Get back to us. Hope this helps. BTW, how old are those O2 sensors? Just checking. Most people never change them until they are bad, but every 50K miles should be the max for them. I doubt they are your problem though (usually not related to what you are describing), but I just wanted to check. im going to test fuel pressure by tomorrow, and hopefully get a volt meter to check the TPS. hadnt thought about cleaning iac and maf. im unsure how old the O2's are. the car has an o/r pipe so i believe the rears have the MIL's on them. unless fox's are weird. lol but again wouldnt the o2's and even the tps and things cause a CEL. i know the CEL works as it comes on during start-up then goes off. There are no rear O/2 sensors just one set and removing cats will not throw them off on the old EEC-IV. No MIL eliminators needed. Throwing a CEL is something a Fox Mustang does very rarely. It usually has to have a sensor completely unhooked for it to throw a CEL or be at the point of almost not running at all. That is actually why they are still so popular to modify with the stock computer (MAF-type), they are so damned forgiving and adaptive. It is just a pain when you are trying to track down an issue such as this. It is usually a trial and error sort of thing. I guess that is one good thing about the new OBD II: the diagnostics can be a big help. BTW, make sure the EGR is clean and functioning properly. I forgot to mention it.

Check you timing. While you are at it bump it up to 13-14 BTDC unless you still want to run 89 octane. The reason I say to check it, is that it may be way too slow. I had a local guy once with a junk yard 5.0 in his old Fox GT that was whooping up on a local 355 CI S-10 and he found out that after 4 races (all wins) the S-10 guy was stepping it up. He asked me to check his car. It still had the factory silencer, etc., plus his timing was just a couple of degrees above 0!!!! :lol: I gave it the famous "10 minute tune up", put 32 heat range Motorcraft plugs in, etc. and he almost wrecked it when he took out of my driveway. :lol: He beat the S-10 again...

i dont have a timing light and i have to drive 1 hour to get my buddy to do it. i dont kno anyone local. i was unaware of the rear o2 on the fox. i knew the EEC was forgiving...lol im hoping to get a voltmeter on the TPS and fuel pressure checked tomrorow and ill report back.

think i found the problem and im quite embarresed to say the least. i checked these multiple times and just overlooked it. sometimes things can be so simple and you try to make it too difficult. :oops: still cant believe a CEL wasnt thrown....damn these fox EEC's must be VERY forgiving.

That wouldn't throw a cell. Would cause a miss though. Not really a surge... A miss for sure. First FRPP wire I have ever seen burned. I got rid of MSD super conductors because of that, and have never had a problem with FRPPs (which are made by MSD by the way)

i guess the surging came from when it was actually firing on all 8 and not on 7. maybe. im going to get some wire boot covers...like header wrap for the wires. i dont have room to change anything with these equal length shorty's.

ever used these? what ya think of these boot covers? local and cheaper. Autozone - $35 Accel / ACCEL Pro Sleeve Boot Guards (8 Pack) About this product:Part Number:170081Weight:0.62 lbs.Pricing: $34.99Availability:Store:Normally stocked at your local store. Online:Ships within 2 business days advance - $67 for same thing Accel Spark Plug Boot Guard Tape: Pro Sleeve Boot Guard; 8 PackPart Number: 170081(click image for full-size view)PricingOur Price:$67.77 Availability Ships in 1 business day (2.00 lbs.) Warranty1 Year Limited Warranty i hate autozone....but for the price difference.... doesnt advance price match?

realized the pic didnt show

Those would help, but you need new wires no matter what. $39 from Summit.

why do i need new wires? only one got toast? and ill have a new #3 wire here tomorrow.

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