MAS

Hey, lately my (stock) 87 924S has been developing a slight engine hesitation under hard acceleration above 4,500 rpm. It will usually only happen in 3rd or 4th gear.
This is only noticable on the highway. Around town the engine is a smooth as silk. Also, the hesitation does not happen in hard take-offs in 1st and 2nd.

If I back off slightly from the gas when I get the hesitation, it stops.

It's not the biggest deal, because 95% of the time I do not drive the car full out in 3rd or 4th gear.

A friend of mine who was with me said that it felt like a bad spark plug, plug wire, or connection. Any ideas?

Thanks

-MAS

scular

I agree, change the filter, but also put a bottle of fuel injector cleaner in the tank on next fill up. It cleans a lot of crude out of the lines, pump and injectors.

You are running premium from a good gas station (read high volume, no water in tanks) right.

TazioNYC

I'm getting this same thing -- running 93 premium gas from the usual (Mobil, etc...)...anyone have any ideas? happens @ 4K, it's like a stutter, feels like something is slipping.

Reimu

Same here, but it only happens every once in a while. Usually around the bottom end of the rev range for me though.

2BWise

I had a similar thing last summer and fall. It seemed that in 1st and 2nd in would drive right thru it, but in 3rd and 4th around 5k it was a violent stutter. Caused me to hit the visor a few times. Turned on to be a bad DME. As bad as it sounds to have to consider a bad DME as well, don't rule it out. See if you can find someone to swap with and test it. Might as well test it than buy one first.

Reimu

I don't think we're having a hesitation quite that violent.

Keithr726

When you put in injector/fuel system cleaner use chevron. My old 83 ran weird on STP.

2BWise

Let me redefine violent. Full throttle, then the engine cuts out, wasn't expecting it, and my head would occassionally make it into the visor. Wouldn't you consider any unexpected cut at full throttle to be violent?

jtsporsche

im not sure if this is wht you people are talking about, but my 87 924S dosent seem to have as much get up and go @3K in 3rd as i think it should, or do i overestimate the porsche?

TazioNYC

no, this is a stutter under hard acceration...the same effect would be if someone yanked your foot off of the throttle, but a series of them. Enough to make you want to back off.

2BWise

Is it throttle position dependent? Will it only happen if you're at WOT? If you back out of the throttle slightly does it continue to stutter?

TazioNYC

This doesn't have to be at full, for me...just aggressive, coming off of an on ramp or passing type of maneuvers.

Keithr726

+1 for the TPS

Z-man

Could be a slipping clutch. When was your clutch replaced last?

-Z

2BWise

MAS - I'm thinking its your DME, sounds nearly identical the DME issue I had

TazioNYC - +1 on TPS