Engine missing a beat

[curlyearly]

Hello all, in need of a little assistance please.
Have a 4.5 petrol whose engine recently started missing a beat. Firstly the vehicle is well serviced and low mileage.
The symptons are; drives fine under light throttle / flat roads. Under a little more than gentle throttles or medium / steep hills the engine starts to miss a beat. At first I thought a plug lead(s) had come loose as under light loads they would not be evident but under heavier ones they would.
As this coincided with a service I asked the garage to change the plug leads / distributor cap at the same time as the car is 11 years old. Sadly this did not work.
Now heres a puzzling part of the jigsaw. For the first 5-10 minutes after starting in the morning the engine runs fine. This is not just when its cold but as the engine warms up quickly, also when its warm.
On this basis I wondered if it was a sensor gone down.
Have tried redex and this did not work. The problem is so bad that when I recently went up a steep hill (1 in 4) I had to put it in low range first to get up and then it struggled.
Help please....

 

[NaterGator]

Do you have a check engine light?

 

[gray]

Hello all, in need of a little assistance please.
Have a 4.5 petrol whose engine recently started missing a beat. Firstly the vehicle is well serviced and low mileage.
The symptons are; drives fine under light throttle / flat roads. Under a little more than gentle throttles or medium / steep hills the engine starts to miss a beat. At first I thought a plug lead(s) had come loose as under light loads they would not be evident but under heavier ones they would.
As this coincided with a service I asked the garage to change the plug leads / distributor cap at the same time as the car is 11 years old. Sadly this did not work.
Now heres a puzzling part of the jigsaw. For the first 5-10 minutes after starting in the morning the engine runs fine. This is not just when its cold but as the engine warms up quickly, also when its warm.
On this basis I wondered if it was a sensor gone down.
Have tried redex and this did not work. The problem is so bad that when I recently went up a steep hill (1 in 4) I had to put it in low range first to get up and then it struggled.
Help please....

Have you checked what is coming out of the spark plug leads?ie: power module, coil, etc? May be a weak spark
Also, timing not keeping up, etc?

Other thought is bad cats; when cats get hot, if they are getting
plugged/melted, they produce an increase in back pressure which will cause the engine to miss and then run like sh-t, and then not run at all.


Good luck.

g

 

[IdahoDoug]

Be good to know what year/tranny/country and miles.\

DougM

 

[curlyearly]

Its had new leads / plugs / distributor cap. Lovely big spark.

A friend says it is blocked injectors. Any thoughts on this.....

 

[cruiserdan]

Do please elaborate on what vehicle you have and what engine. Since you are posting here I would assume a petrol 80 with either a 1F-zed or a 3FE. It's important to know the specifics in order to be able to make an educated guess.

Have you inspected the air intake hose for cracks?

 

[mkfour]

You mentioned that you had the truck serviced. What did they do other than the cap, plug heads, etc..

On my other car, I had the same symptoms that you are experiencing. It turned out to be overheating. Oddly, the temperature gauge read in the normal range. Ran fine under light throttle, but give it some gas an it would bog down. So just in case, if the technicians haven't looked into it already, check for a blown HG or overheating causes.

 

[curlyearly]

Uodate to replies so far

Engine is a 4.5 petrol 1FZE. 76 miles. Full service history. No obvious water leaks in as much as expansion resevoir is full.

It continues to puzzle me in that for the first 10 minutes from cold it runs perfectly which includes about 5 minutes on a warm engine. Then the fault begins, not gradually, but one minutes its not there, then it is. Is there a cold / hot sensor to look at?

What about the fuel injector theory?

 

[NaterGator]

Fuel injector theory is possible, which is why I asked if you have a check engine light. Or access to any sort of OBD-II equipment? It should be a 96, being 11 years old

Do please elaborate on what vehicle you have and what engine. Since you are posting here I would assume a petrol 80 with either a 1F-zed or a 3FE. It's important to know the specifics in order to be able to make an educated guess.

Have you inspected the air intake hose for cracks?

Not to be a jerk guys (or single you out cdan), but he did specify everything in his first post if you look carefully He said it's a 4.5 petrol (obviously 1FZ) and 11 years old, which is all the basic info we need.