HT4100 4.1, 4.5, 4.9 Discussion, Finally Solved 4.1 Hesitation: Coil & Plug Wires in Cadillac Engine Technical Discussion; My 87 Eldo has had a worsening hesitation problem over the last 6 months. Within the last 2 years I ...
My 87 Eldo has had a worsening hesitation problem over the last 6 months. Within the last 2 years I had replaced plugs and wires. Then recenlty replaced cap, roto and module. Still ran rough.
Took to local shop. Guy found coil was arcing. Replaced and ran better but still had high speed miss/hesitation. Checked fuel pressure and it was a little low. Replaced fuel pump but no change in hesitation. Mechanic said he didn't know what else to check.
I started looking for a Cadillac mechanic: hard to find (other than dealer). Was driving home one night and I recalled having had plug wire problems on a previous car. So I popped the hood when I got home, turned the lights off, and the plug wires were arcing like a Christmas tree.
So the cheap wires I put on a couple years ago had failed.
So if you are having hesitation problems, check the plug wires and don't go cheap with the replacements.