tbanasiak

This started @ 2 months ago and doesn't happen all the time. I only drive the car once in a while but need some thoughts as to probable cause. Driving along at speed the car all of a sudden stops accelerating like I hit the brakes or down shifted. It's only momentary and then she drives along fine. I replaced the fuel pump relay but still happened. The car doesn't die just the momentary loss of power.

whalebird

Ignition switch possibly? Do you have a big wad of keys on a keyring? Get rid of them if so.
Before anything else, check your battery cables in the trunk. Certainly the terminals on the battery and the smaller wires that bolt to the terminal(+), but also the ground end that bolts to the front bulkhead should all be checked.
Give us the year of your car and any modifications or repair/maintenance thats been done recently.

tbanasiak

i'm big on only having the car key, so never more than just the car key EVER. all electrical things still work when symptom occurs and engine continues to run there is just a momentary hesitation if you will as if the fuel is being starved to the engine. I ordered a new fuel filter from pelican this morning. from what i've read could be a clogged fuel filter. not sure how old the current one is. I purchased the car last july and i haven't replaced it as of yet. The car is a 1989 911 cabrio with the 3.2 l engine. only mod was a K&N air intake by previous owner.

gaparkin

sounds like the same problem my father had with his truck. I don't know if your car is equipped with it though,but could it be the throttle postion ssensor.

tbanasiak

i will add the TPS to the list thanks.

Billm

Does this happen at a certain rpm in every gear, only when driven a distance? Any commonalities of when it happens can help diagnose.

tbanasiak

Well I don't drive this car daily and out of lets say out of 20 drives it might occur 1 time for a couple seconds. Usually I'm cruising along in 5th gear at @45 MPH. I got my new fuel filter today and installed it so I plan on going out in a bit for a drive.

tbanasiak

Those drives are short trips maybe 10-20 miles tops.

JABSEA

Off the top of my head, but 45 mph in 5th sounds like you're lugging the engine a bit. Does it ever happen at 45 in fourth?

tbanasiak

yes it happens in 4th, maybe my speed in 5th was more around 50. i know 48 is true shift speed for 5th. today i took MAF off and cleaned real good also cleaned the throttle body. went for short drive and no problems noted, actually acceleration felt better. I'm gonna take it for a drive later longer in duration and see what happens. I did some reading last night on 6speed forum and this was a topic, apparently for many the K&N oiled filters were causing same problem i have. My K&N filter could be the culprit as with those other folks. I am going to order a AEM filter and get rid of the K&N. hopefully problem solved.

theiceman

Cht sensor is dieing ?
I would put a new one in regardless and also swap out dme relay to eliminate

Btw who puts In a fuel pump without changing the filter first. That is an expensive way to TS an issue
If it isn't any of those issues my guess is electrical. Have you done the basic plug cap and wires ?

tbanasiak

iceman this is what i have done already.................changed relay, fuel filter, spark plugs (due anyway), rotor ( cap was fine), checked wiring (all good).

The cht is on order and will install next week. thanks for input!

tbanasiak

Well after cleaning the MAF and throttle body I went for a drive and she drove fine. Gonna drive her to work today and see what happens.

Rick K

Could be early signs of a failing fuel pump as well...

whalebird

Failure mode of a coil can be hard to diagnose, but is often found under various part-load/part-throttle conditions.