intermittent stumble

[scottinAZ]

having a bit of a go with my M50 swapped 87 cabrio. getting an intermittent stumble while cruising, no rhyme or reason to when it does it, but when it does, and it is becoming more frequent, it loses power and will not rev, for about 3-5 seconds and then recovers, and acts normally. only troubleshooting I have had time to do is replace the fuel pump relay, and check for codes with the stomp test (no dice, no codes). I am leaning towards either a fuel issue (poss bad pump?) or the main relay. relay will be swapped out tomorrow along with a once over checking for obvious loose connections on the main power wires mostly at the starter.

anyone else have a similar issue that they would like to share the outcome on, to maybe give me a direction to lean in?????

[drez14]

My vote goes to bad fuel pump or dirty FP strainer or clogged fuel filter. I had a problem with loss of power at higher rpms. My tank was rusted out which screwed up my pump and clogged my filter. Replaced all 3 and everything is peachy.

try driving around with the seat and FP cover off. My pump definitely had an intermittent bad "whine" which was a dead giveaway for bad pump.

Even though my problems happened at high RPM, if its clogged enough, it could be your problem too.. I think its more filter than pump though

[7pilot]

Is the DME getting a consistent road speed signal from the Dash?
Is the DME getting a good 12v connection?


m

[scottinAZ]

Is the DME getting a consistent road speed signal from the Dash?
Is the DME getting a good 12v connection?


m

Yes on both counts.

Found bad fuel lines coming from the frame rail in the engine compartment to the motor (orignial to the car/engine it looked like, lots of deterioration of the liner...). No problems as of yet, but the last time I thought I had it fixed it took another 300 miles to manifest itself again. replaced the main relay as a matter of course, so we shall see if it decides to play ball again