engine hiccup

[oldrocker]

While driving an 800 mile trip my 86 Esprit HCI gave a "hiccup" as I lifted my foot gently off the gas to cruise. This began to happen at about the 400 mile point. As the trip grew longer the hiccup began to happen more frequently as I backed off the gas slightly. Closer to home it got so bad I thought I would not make it there. When stopping for a fill up it would not idle without bumping the gas. Strangely, while running at speed the engine did not sputter or backfire while taking the gas only when backing off slightly and then only a hiccup not a backfire or sputter or pop. The problem felt like it was running out of fuel when the hiccup occured. I am assuming this is a fuel pump or blocked filter problem and am presently waiting for new pumps to arrive. One last observation; now when cold starting, the engine will not idle without bumping the gas. Any suggestions or similar experiences and solutions appreciated.

[oilchange]

does it have a throttle position sensor? I dont know much about the older carbed cars and how they run but a sensor of some sort or a fuel problem (blockage?) has probably occured. It is probably a cheap fix, so many of these things are. If someone says ' Lotus eh? that'll be XXX thousand, dont listen they're talking bollox. Bound to be.

O C

Red 94 S4

Edited by oilchange on Sunday 22 April 20:25

[oldrocker]

Thanks for the reply. You seem to agree with the fuel problem as being blockage or shortage of fuel. That is certainly what it seemed like. It does have a TPS but I do not believe that is the trouble unless someone can verify that with some certainty. It just did not act as an ignition or electrical problem as there was no backfire or pop.

[anonymous-user]

If it fuel starvation I would say it would be seen at high revs, I assume a 86 is running 45 Dellroto's, if so it will only tick over smooth if the timing is right, I'd look if the distributor has moved, the std advance on the distributor is around 25 deg over the first 3000 rpm, so at say 8-10btdc at 1000 rpm, you will have 35 at 3500 rpm and above, but if the distributor moved you may have say 15 at 1000 but you would only have 40 at 3500 and above, my engine will run OK at 45btdc at at higher rpm but would not tick over well at 15deg of advance at tick over.
By the way, I'd worry if the car did tick over cold without blipping the throttle, as it would be way to rich when worm, (assuming you have the chock disconnected.