New to me 95 NAS D90. Hard starting, erratic idle, dies at idle, dies coasting at low power, light spark knock right bank, hard to drive without "drive line buck" at low thtrottle settings. These items in "search" hit about a third of all time posts.
- Presale PO had shop #1 install reman distributr, plugs, wires for starting problems. NO real improvment. Shop also reports blown head gasket. Renegotiated the purchase.
- I had shop #2 repalce headgaskets- it was a known problem. "Surely will fix the starting problem". Still won't start or idle well.
- I changed IAC and cleaned ecu contacts- some were really corroded. Little better here. Still spark knock though lite.
- Next shop #3 deduced fuel pump weak based on pressure reading. I saw the rust on the bolts back there and told them to have at it. Told me if I ever had another vehicle just like it take it somewhere else- that perversly felt like good value.
- Starts better but not quickly.
- Lite sparknock worrisome so I get a modern new timing light for use. After having to buff the balancer to read marks I found the dist was turned so far the vac advance houseing hits the tstat housing, I mean really!?!? Needs to be pulled and resest with better adjustibliblty but it runs so well for the first time in 6 months its gonna stray this way for a while.
Now it starts first time and idles rock solid.
Conclusions, don't trust anyone to do the simplest items unless you verfiy behind them. The first guy put the distributor in wrong. The second guy did the headgaskets by marking the dist base and put it back the way he found it, wrong.
The third guy found fuel pressure and quite hunting.
"Driver be not mechanic thy self at own peril in the D90 world."