1986 Mondial Acceleration Problem

I have an 1986 Mondial with 51K miles and it’s in really great condition. The engine had its second 30K overhaul 2K miles ago.

I’m currently experiencing a very strange problem. When the engine is hot, and only when it’s hot, around 4200 rpm’s the engine pulsates during acceleration until around 5200 rpm’s, then is sort of smoothes out. Before the engine gets hot it accelerates perfect. The crankshaft sensor (1 of 2) has been changed and that stopped the pulsating for a few days but it’s back. I’m thinking the problem might be in the electronic ignition module but I’m not sure. All the fuel injectors have been cleaned and tested, new sparkplugs, wires, and new coils.

Has anyone heard of this type of acceleration problem?

Thanks.

1- Have you Inspected or Replaced the Plug Wire Extenders? They are easily inspected and when bad you will see a small dusty or darkened spot on the side (this spot is actually a tiny hole) of the lower portion where they push onto the plug.

2- are you sure the wires speced out on an Ohm Meter after instalation(I've seen more than a few "Bad Sets" of New Wires)?

3- are you sure the Distrib Cap Electrodes & Rotor Tip are Clean & the Center Carbon Tip in Good Condition?

It could be a module also, but we need to eliminate the simple & more suspect things first.

[rscapri2600]

I had a similar problem on my 85, eventually traced it to a faulty fuel pump after replacing pretty much everything else, plugs, caps, rotors, wires, plug extenders etc. Fuel pump would test and work fine when the car was first started but after driving the car for over 2 hours, the hesitation would start and then I finally did the fuel pump test again. It would still pass the pressure tests but would only flow 90% during the flow test. IIRC, it was supposed to flow 1 liter of fuel in 1 minute, and the pump only did a bit more than .9 liter which is pretty close. I replaced it and the acceleration hesitation went away. However, my engine never did smooth out and got worse the harder I accelerated so it may be a different issue.

Joe Craven