I know this subject has been covered but without any real answers being given. We have had many theories about fuel, coils etc but not one of these single things seem to be the answer.
Here is what happened to me on my trip down to Bathurst over the weekend that made a 3hr trip into an 8hr one
I left home at about 11am in 30odd degree heat. I had already done over 50k's before I left to go into town,so the engine was warm when I left. About 30k's down the road the tacho started to jump a little but there was no noticable difrence in the revs of the engine so I dropped my speed to 90/100k's (open road limits up here) and kept an eye on everything.
After travelling another 100k's the tacho was jumping more & more and there was a distinctive lack of power up hills (these were big hills I will add).The temp gauge was a little higher than where it normally sits ie: on the bottom line of the normal section, but was still under half way. After about another 30k's there was a huge backfire (read like a cannon going off). and a surge started to happen every 15-30 seconds. This surge wasnt a huge one but enough that my passenger then realised something was amiss.
I slowed to about 80k's and being in the middle of nowhere I kept on going slowly. The backfiring gradually got worse as did the surging. These got to the point that I could only travel at about 40k's and it was basically the forward surge that kept me moving. If I took my foot of the accelerator it would stall so I kept my foot just barely touching it to keep going.
The temp of the day would have been about 35 degrees by this stage & the whole car felt hot even though the temp gauge was still only reading just under half & I knew there was still water in it. The fuel pump was a lot louder than normal as well so I thought that was the problem.
It got to the point that I had to stop and got towed into the next town. When we got to the mechanics the car had cooled as I parked under a tree. The mechanic took her for a drive & there seemed to be no problem at all
He used a computer to check the leads and there was nothing amiss there & he suggested that the filter in the fuel tank was the problem & it must have cleaned out on the back of the tow truck.
I slowly got to Bathurst by stopping at all the towns on the way & letting her cool down.
I started realising this wasnt just a fuel problem when I left the last town I stopped in at about 6pm......The air was a lot cooler outside and the surges were getting less and less just as they had started getting more & more .....
The closer to Bathurst I got the better she ran......
I only drove her once over the weekend and had another guy come to see what she would do as the afternoon was warming. When cool she was great ...... as soon as the temp gauge moved over the bottom line of normal the tacho started again........so did the backfire
On my way home yesterday the weather was cool & the needle never moved and the fuel pump sounded like normal. Lets say the trip home was vastly faster than on the way there.
I have so far replaced the front fuel filter, air filter and used injector cleaner to no avail....... all I seem to need is cool weather......... not good when our summers here can get to 40odd degrees
So my question is ........... What is it that is being affected by the heat ..... is it only the fuel pump, the electrics ...... or some other thing that we will never know & have to not use our cars during summer
Ohhhhhh for those who dont know ..... shes a 1988 EA Spac CFI 3.9