5 replies to this topic

[Tim Spittle]

Anyone experienced a engine bobble under full throttle that got progressively worse longer engine was ran. Took my 1997 spec miata to the track last weekend and car ran fine first session, after that car would stall for a second when shifting into fourth, just a momentary loss of power and then would pick up. This got worse the longer car was ran, until full throttle would cut power and I would have to back off and feather the throttle to get the car to run. When I brought it into paddock and let it sit for a while, I would get two or three laps, then the bobble would be back....again getting progressively worse until I thought it was not going to make it back to garage.

Things done, plugs, wires, fuel filter...don't want to just throw parts on, any suggestions would be greatly appreciated. I am going to pull the fuel pump tomorrow and look at the strainer.

[Glenn]

Anyone experienced a engine bobble under full throttle that got progressively worse longer engine was ran. Took my 1997 spec miata to the track last weekend and car ran fine first session, after that car would stall for a second when shifting into fourth, just a momentary loss of power and then would pick up. This got worse the longer car was ran, until full throttle would cut power and I would have to back off and feather the throttle to get the car to run. When I brought it into paddock and let it sit for a while, I would get two or three laps, then the bobble would be back....again getting progressively worse until I thought it was not going to make it back to garage.

Things done, plugs, wires, fuel filter...don't want to just throw parts on, any suggestions would be greatly appreciated. I am going to pull the fuel pump tomorrow and look at the strainer.

If its not the pump and or strainer, look at coils.

[Qik Nip]

I agree with Glen. I'd look at the coil pack. Sounds like with heat build up, insulation quality lessens and spark falters.
Rick

[Keith Novak]

This comes up a couple times a year. 1st I'd remove and clean all the grounds, PPF, back of the intake, front bracket, main engine on the firewall. That the leading cause. Don't just check that they feel tight. I put little star washers under all of mine. People have replaced a lot of parts before they found a bad ground. Then I'd check the coil. People always say the CAS but I don't remember that being common. Occasionally the ECU connector can be bad. The fuel pump strainer is a common one but typically on corners I think. When it only happens hot it's usually electrical.

[Ron Alan]

I concur! Heat! Coil or something that is affected by heat!

[Tim Spittle]

Thanks a bunch for the replies...., I pulled the fuel pump and the strainer looks like it was made of copper..car sat for awhile, I am hoping this fixes it, but the coil was next on the list, again Thank you for the input on this.