Hesitation at around 5000RPM

[Art138]

Was researching for past threads on the issue to no avail; today I was doing some spirited driving and noticed the car hesitate several times as I reached around 5000RPMs. I have the Heffner tune,pulley,accufab single throttle body,Accu cat back exhaust. Checked the pulley belt and does not appear to be loose....any suggestions?

 

[BlackICE]

Could be as simple as new spark plugs. I had mis-fires a loss of power around 5000 on during a dyno session due to bad/old plugs.

 

[nota4re]

Yeah, I say sparkplugs too. For your set-up I would recommend NGK TR6IX. Gap them pretty tight - maybe 0.028.

 

[dbk]

Nuked plugs have always been the cause when that happens to my car. Typically I run a lot of race gas so it's not that infrequent of an occurrence, but I always know instantly when it starts stumbling over itself that I've been running C16 long enough between changes.

 

[Art138]

Thanks for the feedback, I have approx 1,600mls on the car,but worth a try......

 

[2112]

NGK plugs are awesome, and I usually prefer everything American made.

 

[jcthorne]

Pay attention to the gap. Even the stock plugs need to be regapped if running the higher boost with a pulley installed. 0.028 was already suggested. Stock is near 0.054, much too large for 16lbs of boost. I too have had great results with the NGK TR6 plugs for a number of years. (GT500 and supercharged Cobra before that). I usually get about 10 or 12k miles on a set before they need cleaning and regap. At 2 bucks a piece, I just replace them if I pull them.

 

[STORMCAT]

Was researching for past threads on the issue to no avail; today I was doing some spirited driving and noticed the car hesitate several times as I reached around 5000RPMs. I have the Heffner tune,pulley,accufab single throttle body,Accu cat back exhaust. Checked the pulley belt and does not appear to be loose....any suggestions?

Did you get a check engine light ? If it is only happening above 4000 RPM on a hard pull I bet $100 if you change the $12 fuel pump relays it goes away.. I had to change my secondary relay twice.. I had a post about my problem and this has also cured a few others.. It's the easiest thing to try and from what you wrote that is my diagnosis ..

 

[KJRGT]

What is the recommended miles to change out the original plugs?
Normal street, freeway driving and 4-6 track days per year.

 

[Art138]

Thanks to all,changed the plugs to NGKs TR6IX (iridium) and just in case the two fuel relays.....gapped the plugs at .028.......... problem solved.

 

[BlackICE]

Thanks to all,changed the plugs to NGKs TR6IX (iridium) and just in case the two fuel relays.....gapped the plugs at .028.......... problem solved.

Nice to hear that you solved the problem! :thumbsup

 

[paul b]

Thanks to all,changed the plugs to NGKs TR6IX (iridium) and just in case the two fuel relays.....gapped the plugs at .028.......... problem solved.

What plugs were in originally.

 

[twobjshelbys]

Way cool! Note made in the book for future reference!

Gotta love this forum. So much good info.

 

[Art138]

What plugs were in originally.

Motorocraft Platinum AGSF -22FM1 were the ones I removed...

 

[STORMCAT]

Thanks to all,changed the plugs to NGKs TR6IX (iridium) and just in case the two fuel relays.....gapped the plugs at .028.......... problem solved.

Good to hear she's back to normal ,, Me being the curious cat I am I would have done the corrective measures separately and try to isolate what it was. There wasn't a lot of miles on the plugs that's what made me think it was something else.. But the best news is she's back to normal and the NGK's are the plugs or choice !!