Problem with rough idle. Part 1...

On my new ride, it had a very bad idle. Even engine stalled 5 times per day. It's a very frustrating for me.

Then I started to seach for the culprit. First thing suspected is vacuum leaked.
After changed all the related vacuum hose, the idle still rough.

I bought a detomaso Throttle body although I know its not identical. But I still want try to mod to fit it. It's no luck. The TB can fit it nicely but idle still very bad due to different method of idle control. Then I decide to cleaned and put back original TB. Idle not very good after first start. Did a TPS swapped, and it seems idle bit ok. Drove it for 1 day and the problem came back. Now it really gave me headache.

I keep calm for a few days and start listing what is the possible culprit.
Here is the list.
1-vacuum leak
2-O2 sensor (replaced on 9 Jun 14 )
3-TPS adjustment
4-spark plug
5-spark plug cord
6-distributor adjustment
7-clogged fuel filter
8-weak fuel pump

So yesterday I made a decision to repair the cheapest solution first. What i did is
1-inspect spark plug. Whitish color. I guess a bit lean fuel.
2-removed fuel filter.
3-adjust TPS.
All those step did not cost any money.

After finish the steps above, started the engine and observed for idle. So far so good, idle are stable but a bit low rpm. Idle screw adjusted to compensate low rpm.

Today, drove it to work. Idle are steady and stable all the way. I hope the problem has been vanish.

I think TPS adjustment has solved the problem.

IMHO, no need to change TB assy, but try to adjust TPS according to manual. Most people will replace TB assy when they got rough idle problem. And problem solved. It is because new TB have good TPS alignment.


CONTINUE TO PART 2...