Error code P1627

Could loose ground rusty fuel tank,

Sorry to say your beyond a volt meter

You need a scan tool to look at fuel trim

A scope to look at oxygen sensor switching times

Need to know fuel pressure at motor with gauge or scanner

With a turbo your going to need to know about all the related
components involved around it's function

You need a shop that likes a Saab & is good with them

The car only blue books for about $3000. I hate to suggest it but financially it may be better to cut your losses on this one. A used engine with 7000 miles on it for this car could have been purchased for $1200.

The code that you are getting does not necessarily mean that the crank sensor is defective. Those codes are to be used as symptoms only. If the crank sensor is bad the car won't run at all.

If it's running rough you need to check the health of the ignition system, fuel system, and the timing.

Starting with the easiest to the more difficult.
1. Pull the spark plugs and read them. Are they fouled/damaged/wet/burnt?

2. Check the engine compression. Is the compression low?

3. Check the timing marks. Did the timing belt slip off a tooth with the cam gear? Is the timing belt worn out? Make sure these marks line up with what your manual shows.

4. Check your fuel pressure with a gauge. Does it match what the manual states it should be?

5. Is the coil pack weak, out of tolerance? Check it with a multimeter, make sure the ignition wires are in good shape. If you've never changed them, this would be a good time.

If you check these things you should find the problem...throwing parts at it till the problem goes away is the most expensive way to fix it.

take it to dealer

Its possible the gears are not on the right marks.
Have you checked cam timing since replacing the second belt ?

Check fuel pressure regulator vacuum line for fuel in it. Replace FP regulator if it does.

P0300 - Engine misfire detected
P1627 - PCM analogue to digital conversion malfunction.
These 2 often come up together when theres a problem with the fuel level sensor. The sensor sits underneath the filter. Remove its connector. Resistance shold be 80-180ohm. You may also notice weird readings from your fuel guage.

Have a look at the fuel filter bro.

Trouble code P1627 means: PCM A/D Conversion Malfunction

This is a fuel sending unit code and it directly related to you goofy gas gauge. This is a common problem in 2nd Gen Isuzus. The fuel sending unit needs to be replaced. Most places will tell you that you must replace the entire fuel pump assembly module but you can buy just the sending unit.

Other faults to refer this problem and other codes: P0141, P0300, P0404, P1404, P1627, with this synthoms:
hesitates sometimes on takeoff, gas gauge gives random readings(sometimes will read empty, or full, or somewhere in between), Fuel light flashes sometimes.

Hope helps.

a stripped group of cogs on timming belt is most likely ur problem,a new timming belt may not solve ur problem,this is a interference engine ,u may have bent vavles,install timming belt and if it runs,and runs smooth and got plenty of power,then u will be ok